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Fermentation, Volume 9, Issue 7 (July 2023) – 116 articles

Cover Story (view full-size image): Milk, whey and curd samples from five Pecorino Siciliano PDO-producing farms were collected and evaluated for the presence and diversity of mesophilic and thermophilic lactic acid bacteria using culture-based approaches, while individual isolates of Lactococcus cremoris/lactis and Streptococcus thermophilus were characterised. Each farm was observed to contain genetically distinct strains of these species, which form part of the microbiota of the final cheese product. Simultaneously, the overall microbial diversity of the curd samples was evaluated using metagenomic analysis. Understanding traditional and artisanal food production systems is key to supporting regional food production practices and ensuring the consistency of these products. View this paper
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14 pages, 3953 KiB  
Article
Effects of Main Nutrient Sources on Improving Monascus Pigments and Saccharifying Power of Monascus purpureus in Submerged Fermentation
by Yingying Huang, Jiashi Chen, Qing Chen and Chenglong Yang
Fermentation 2023, 9(7), 696; https://doi.org/10.3390/fermentation9070696 - 24 Jul 2023
Viewed by 813
Abstract
Hong Qu (HQ), obtained through fermentation of various grains using Monascus spp., has been widely utilized as the main and characteristic initial saccharification and traditional fermentation starter in the food brewing industry. The quality, color, and flavor of HQ and HQ wine are [...] Read more.
Hong Qu (HQ), obtained through fermentation of various grains using Monascus spp., has been widely utilized as the main and characteristic initial saccharification and traditional fermentation starter in the food brewing industry. The quality, color, and flavor of HQ and HQ wine are closely related to the saccharifying power (SP) and Monascus pigments (MPs) of Monascus spp. In this study, to optimize the culture medium in submerged fermentation by M. purpureus G11 for improving SP and MPs, the effects of carbon source, nitrogen source, inorganic salts, and vitamins on SP activity and biosynthesis of MPs were explored through single-factor analysis and response surface Box–Behnken experiments. The results showed that the optimal medium composition was 6.008% rice powder, 1.021% peptone, 0.0049% CuSO4, and 0.052% vitamin B1. Validation experiments performed under the optimized fermentation conditions showed a significant increase in MPs and SP by 14.91% and 36.24%, with maximum MPs and SP reaching 112.61 and 365.12 u/mL, respectively. This study provides a theoretical basis for enhancing MPs and SP in M. purpureus for HQ production, to improve the production efficiency and shorten the production cycle of HQ-related fermentation products. Full article
(This article belongs to the Special Issue Development and Application of Starter Cultures)
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18 pages, 893 KiB  
Article
The Influence of Cabernet Sauvignon Ripeness, Healthy State and Maceration Time on Wine and Fermented Pomace Phenolic Profile
by Nikolina Lisov, Uroš Čakar, Danijela Milenković, Maria Čebela, Gorica Vuković, Saša Despotović and Aleksandar Petrović
Fermentation 2023, 9(7), 695; https://doi.org/10.3390/fermentation9070695 - 24 Jul 2023
Cited by 8 | Viewed by 1337
Abstract
The phenolic composition and antioxidant activity of wine and fermented pomace (FP) from Cabernet Sauvignon grapes harvested at three ripening stages were evaluated using LC-MS/MS and spectrophotometric analyses. An investigation of grey mold’s (Botrytis cinerea) influence on wine phenolic content modulation [...] Read more.
The phenolic composition and antioxidant activity of wine and fermented pomace (FP) from Cabernet Sauvignon grapes harvested at three ripening stages were evaluated using LC-MS/MS and spectrophotometric analyses. An investigation of grey mold’s (Botrytis cinerea) influence on wine phenolic content modulation was conducted as well. Finally, the influence of the plant’s ripening stage on the dynamics of the phenolic compounds extracted from wine and FP obtained from fully ripe grapes was evaluated. In this study, the content of catechin, epicatechin, quercetin, and p-coumaric, gallic, and syringic acids was analyzed. Wine and FP were obtained after extended maceration during the spontaneous and inoculated fermentation of fully ripe grapes. When comparing the wine and FP obtained from véraison, fully ripe, and overripe grapes, catechin was the most abundant in wine (40.13 ± 3.25 mg/L) and quercetin in FP (10.96 ± 0.14 mg/kg). A decrease in analyzed phenolic compounds was noticed in wine produced from grapes affected by Botrytis cinerea, and the highest depletion was found for quercetin. The use of a winemaking technique that involved differing maceration periods and inoculation using yeasts as well as spontaneous fermentation significantly modulated the phenolic content of derived wines and FP. The dynamics of the phenolic compounds extracted into wine, evaluated using a principal component analysis (PCA), highlighted contents of catechin and epicatechin. After a decrease in maceration, the PCA revealed a notable content of gallic and syringic acids, as well as quercetin, in samples of FP. This study offers a perspective for future research and the development of functional food with a high content of phenolic compounds originating from red grape products, such as wine and fermented pomace. Full article
(This article belongs to the Special Issue Nutrition and Health of Fermented Foods, 2nd Edition)
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14 pages, 2370 KiB  
Article
Production of 2,3-Butanediol by S. cerevisiae L7 in Fed-Batch Fermentation with Optimized Culture Conditions
by Guoxu Ao, Shanshan Sun, Lei Liu, Yuhao Guo, Xiujun Tu, Jingping Ge and Wenxiang Ping
Fermentation 2023, 9(7), 694; https://doi.org/10.3390/fermentation9070694 - 24 Jul 2023
Viewed by 930
Abstract
As a chemical platform, 2,3-Butanediol (2,3-BD) has been widely applied in various industrial fields. In this study, to enhance the production of 2,3-BD by Saccharomyces cerevisiae L7, Plackett–Burman (PB) multifactorial design, the steepest climb test and central composite design (CCD) were employed to [...] Read more.
As a chemical platform, 2,3-Butanediol (2,3-BD) has been widely applied in various industrial fields. In this study, to enhance the production of 2,3-BD by Saccharomyces cerevisiae L7, Plackett–Burman (PB) multifactorial design, the steepest climb test and central composite design (CCD) were employed to optimize the culturing conditions of S. cerevisiae L7. The results show that acetic acid, peptone and glucose were contributing factors for 2,3-BD production. Subsequently, a satisfactory production of 2,3-BD (13.52 ± 0.12 g/L) was reached under optimal conditions, which was 3.12 times higher than before optimization. Furthermore, fed-batch fermentation was carried out under optimized culture conditions, and a higher production and yield efficiency of 2,3-BD were achieved (21.83 ± 0.56 g/L and 0.15 ± 0.01 g/g, respectively) when glucose (20 g/L) and acetic acid (0.2 g/L) were added at 12, 24, 36, 48 and 60 h. Therefore, the production and yield efficiency of 2,3-BD were higher than those without fed-batch fermentation (61.46% and 58.51%, respectively). These results provide good support and a technical foundation for the large-scale industrial production of 2,3-BD by Saccharomyces cerevisiae. Full article
(This article belongs to the Special Issue Yeast for the Production of Biochemicals and Biofuels)
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25 pages, 373 KiB  
Review
Potential Effects of Prebiotics on Gastrointestinal and Immunological Modulation in the Feeding of Healthy Dogs: A Review
by Mariana Pamplona Perini, Vivian Pedrinelli, Pedro Henrique Marchi, Lucas Ben Fiuza Henríquez, Rafael Vessecchi Amorim Zafalon, Thiago Henrique Annibale Vendramini, Julio César de Carvalho Balieiro and Marcio Antonio Brunetto
Fermentation 2023, 9(7), 693; https://doi.org/10.3390/fermentation9070693 - 24 Jul 2023
Viewed by 2862
Abstract
One of the most studied functional foods in dog feed today is the prebiotic. Prebiotics are known for their modulating effects on the intestinal microbiota, fecal characteristics, and the immune system, which promotes beneficial effects to the host. However, with the diversity of [...] Read more.
One of the most studied functional foods in dog feed today is the prebiotic. Prebiotics are known for their modulating effects on the intestinal microbiota, fecal characteristics, and the immune system, which promotes beneficial effects to the host. However, with the diversity of prebiotics in the pet market, there are discussions around which prebiotics to use to stimulate these positive effects. In this case, the objective of this review was to demonstrate the main effects of different prebiotics on the feeding of healthy dogs. Platforms such as Embase, PubMed, and Mendeley were accessed to plot all scientific articles in vivo that reported prebiotics to feed adult or senior dogs. After excluding duplicate articles and without the evaluated criteria, we obtained a total of 36 articles. Our results demonstrated the diversity and concentrations of prebiotics in the feeding of healthy adult and senior dogs. The effects of prebiotics differ according to source, concentration, and length of the supplementation period. Several beneficial effects of different prebiotics have been observed in dogs, such as increased fecal Lactobacilli and Bifidobacteria concentrations and decreased fecal Clostridium perfringens and Escherichia coli concentrations, increased short chain fatty acids concentrations, decreased colonic ammonia absorption, and immunomodulatory effects, such as improved humoral immune response and increased phagocytic index. Galactooligosaccharides, fructooligosaccharides, mannanoligosaccharides, yeast cell wall, inulin, and beta-glucans were the most studied prebiotics, which showed potentially promising effects. This is a review that brings the importance and the modulating effects of prebiotics in the feeding of healthy dogs; the effects help the gastrointestinal tract and the immune system. Full article
(This article belongs to the Special Issue Feed Fermentation: Nutrition and Metabolism)
9 pages, 752 KiB  
Article
Fermentation Regulation and Ethanol Production of Total Mixed Ration Containing Apple Pomace
by Jiachen Fang, Zhumei Du and Yimin Cai
Fermentation 2023, 9(7), 692; https://doi.org/10.3390/fermentation9070692 - 24 Jul 2023
Viewed by 1070
Abstract
To effectively utilize local fruit residue resources and regulate ethanol production in fermented feed, the impact of moisture adjustment, lactic acid bacteria (LAB) inoculant, and chemical additive on the fermentation characteristics and ethanol production of total mixed ration (TMR) containing apple pomace was [...] Read more.
To effectively utilize local fruit residue resources and regulate ethanol production in fermented feed, the impact of moisture adjustment, lactic acid bacteria (LAB) inoculant, and chemical additive on the fermentation characteristics and ethanol production of total mixed ration (TMR) containing apple pomace was studied. The TMR was prepared with apple pomace, corn, wheat bran, soybean meal, timothy, and alfalfa hay. The mixing proportion of apple pomace was 15% based on dry matter (DM). In experiment 1, the moisture in TMR was unadjusted (control) or adjusted to 45, 50, and 55%, respectively. TMR containing 55% moisture was used in experiment 2, and the treatments were control, homo-fermentative LAB (Lactobacillus plantarum, LP), hetero-fermentative LAB (Lactobacillus buchneri, LB), and calcium propionate (CaP). The laboratory-scale fermentation system was used to prepare TMR, and their fermentation characteristics were analyzed after 60 days of ensiling. In experiment 1, the pH of the various TMRs was around 4.1. As the moisture decreased, lactic acid increased (p < 0.05) and ammonia-N decreased (p < 0.05). The ethanol decreased significantly with moisture adjustment compared to the control and the TMR with 50% moisture had the lowest ethanol content (p < 0.05). In experiment 2, LP treatment increased lactic acid, and decreased acetic acid and ammonia-N significantly (p < 0.05), while LB treatment had no effect on fermentation. LP and LB each had no effect on the ethanol content. TMR treated with CaP significantly decreased the ethanol and acetic acid content (p < 0.05), but did not inhibit lactic acid production compared to control. The results confirmed that adjusting the moisture of TMR to 50% and adding CaP could effectively inhibit the excessive production of ethanol in TMR of apple pomace. Homofermentative LAB can better improve the fermentation quality of TMR than heterofermentative LAB, but neither can inhibit the production of ethanol. This is of great significance to the effective utilization of apple residue resources and the promotion of livestock production. Full article
(This article belongs to the Special Issue Recent Advances in Fermented Feed)
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13 pages, 1353 KiB  
Article
Silkworm Pupae Coupled with Glucose Control pH Mediates GABA Hyperproduction by Lactobacillus hilgardii
by Luchan Gong, Tingting Li, Shuyi Lv, Xiaozhou Zou, Jun Wang and Bowen Wang
Fermentation 2023, 9(7), 691; https://doi.org/10.3390/fermentation9070691 - 24 Jul 2023
Viewed by 1134
Abstract
γ-Aminobutyric acid (GABA) is a ubiquitous nonprotein amino acid that has multiple physiological functions and has received significant attention in the pharmaceutical and food industries. Although there are many GABA-producing bacteria, the high cost of strain cultivation limits its food additive and pharmaceutical [...] Read more.
γ-Aminobutyric acid (GABA) is a ubiquitous nonprotein amino acid that has multiple physiological functions and has received significant attention in the pharmaceutical and food industries. Although there are many GABA-producing bacteria, the high cost of strain cultivation limits its food additive and pharmaceutical raw material application. In our study, Lactobacillus hilgardii GZ2, a novel GABA-producing strain, was investigated. We attempted to replace nitrogen sources with silkworm pupae, the waste resource of the silk reeling industry, in GYP complex medium. The GABA titer reached 33.2 g/L by using 10 g/L silkworm pupae meal instead of tryptone. Meanwhile, the pH of fermentation was automatically controlled by adjusting the addition of glucose and monosodium glutamate. Finally, the highest GABA yield and productivity were 229.3 g/L and 3.2 g/L/h in L. hilgardii when silkworm pupae meal was replaced with tryptone combined with glucose and monosodium glutamate feeding. By utilizing the waste resource to reduce the cost of the nitrogen source and automatically controlling the pH in L. hilgardii, a hyper titer and productivity of GABA was generated for applications in the food and pharmaceutical industries. Full article
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14 pages, 2141 KiB  
Article
Interaction and Metabolic Function of Microbiota during Tibetan Tea Fermentation through Bioaugmentation with Aspergillus niger
by Kunyi Liu, Liyan Han, Qi Wang, Liran Yang, Xiangyu Liu, Bin Jiang, Xu Zeng, Yun Liu, Mingyong Li, Wenwen Jiao and Mingli Liu
Fermentation 2023, 9(7), 690; https://doi.org/10.3390/fermentation9070690 - 24 Jul 2023
Cited by 1 | Viewed by 893
Abstract
Developing an effective method to achieve stability and improve the quality of Tibetan tea has scientific significance. Aspergillus niger K1 isolated and identified from Tibetan tea was inoculated in unsterilized or sterilized tea leaves to develop the bioaugmented fermentation (BF) and normal fermentation [...] Read more.
Developing an effective method to achieve stability and improve the quality of Tibetan tea has scientific significance. Aspergillus niger K1 isolated and identified from Tibetan tea was inoculated in unsterilized or sterilized tea leaves to develop the bioaugmented fermentation (BF) and normal fermentation (NF) processes of Tibetan tea. The results showed that BF resulted in infusions with a deeper color, a stronger aroma, and a thicker taste compared to NF. The dominant bacterium in BF was Staphylococcus (23.76%), while the dominant fungus was Blastobotrys adeninivorans (50.95%). Moreover, 859 metabolites were identified, and the level of 90 differentially changed metabolites (DCMs) in BF increased significantly (VIP > 1, p < 0.05, FC > 2) compared to those in NF, while the level of 37 DCMs in BF decreased significantly (VIP > 1, p < 0.05, FC < 0.5). Correlation analysis demonstrated that A. niger significantly positively correlated with theabrownins, caffeine, and glutamylisoleucine (p < 0.05, |r| > 0.8). B. adeninivorans showed significant negative correlations with 1-(beta-D-ribofuranosyl)-1,4-dihydronicotinamide and 2-hydroxyacetaminophen sulfate (p < 0.05, |r| > 0.8). Consequently, the inoculation of A. niger for BF has the potential to alter the metabolites in tea through a synergistic interaction with other microorganisms, ultimately improving the sensory quality of Tibetan tea. Full article
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30 pages, 976 KiB  
Article
Examining the Impact of Substrate Composition on the Biochemical Properties and Antioxidant Activity of Pleurotus and Agaricus Mushrooms
by Panagiota Diamantopoulou, Katerina Fourtaka, Eirini Maria Melanouri, Marianna Dedousi, Ilias Diamantis, Chrysavgi Gardeli and Seraphim Papanikolaou
Fermentation 2023, 9(7), 689; https://doi.org/10.3390/fermentation9070689 - 23 Jul 2023
Cited by 2 | Viewed by 1955
Abstract
The composition of the substrate is one of the most critical factors influencing the quality as well as the nutritional value and bioactive content of mushrooms. Therefore, the effects of various substrates, such as barley and oat straw (BOS), beech wood shavings (BWS), [...] Read more.
The composition of the substrate is one of the most critical factors influencing the quality as well as the nutritional value and bioactive content of mushrooms. Therefore, the effects of various substrates, such as barley and oat straw (BOS), beech wood shavings (BWS), coffee residue (CR), rice bark (RB) and wheat straw (WS, control substrate), on the biochemical properties (lipid, protein, polysaccharide, glucan, ash, and mineral content, fatty acids and tocopherols composition), total phenolic compounds and antioxidant activity of Pleurotus mushrooms, P. ostreatus (strains AMRL 144, 150) and P. eryngii (strains AMRL 166, 173-6), cultivated in ‘bag-logs’, was examined. Proximate analysis of A. bisporus and A. subrufescens grown on two different composts (C/N ratios of 10 and 13) was conducted, too. The whole carposomes, pilei and stipes were analyzed. Results showed that BOS, RB, BWS and CR improved the antioxidant activity of Pleurotus species and their nutritional characteristics. Both pilei and stipes were rich in polysaccharides (27.51–67.37 and 22.46–39.08%, w/w, for Pleurotus and Agaricus spp., respectively), lipids (0.74–8.70 and 5.80–9.92%, w/w), proteins (6.52–37.04 and 25.40–44.26, w/w, for Pleurotus and Agaricus spp., respectively) and total phenolic compounds (10.41–70.67 and 7.85–16.89 mg gallic acid equivalent/g for Pleurotus and Agaricus spp., respectively), while they contained important quantities of unsaturated FAs of nutritional and medicinal importance. Pilei were richer in proteins, total phenolic compounds and enhanced antioxidant activity and reducing power than stipes, whereas stipes were richer in IPSs and glucans compared to the corresponding pilei. Thus, mushroom cultivation could upgrade rejected agro-industrial residues and wastes to new uses as substrates for the production of mushrooms with specific nutritional and medicinal attributes. Full article
(This article belongs to the Special Issue Bioactive Products from Edible and Medicinal Fungi by Fermentation)
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13 pages, 989 KiB  
Review
Fermented Foods as a Potential Vehicle of Antimicrobial-Resistant Bacteria and Genes
by Poonam Gopika Vinayamohan, Leya Susan Viju, Divya Joseph and Kumar Venkitanarayanan
Fermentation 2023, 9(7), 688; https://doi.org/10.3390/fermentation9070688 - 22 Jul 2023
Cited by 1 | Viewed by 2647
Abstract
Fermented food products are widely consumed for their nutritional and health-promoting properties, earning them a central place in diets around the globe. However, these foods can present a paradox, as they have the potential to harbor not only beneficial probiotics but also antibiotic-resistant [...] Read more.
Fermented food products are widely consumed for their nutritional and health-promoting properties, earning them a central place in diets around the globe. However, these foods can present a paradox, as they have the potential to harbor not only beneficial probiotics but also antibiotic-resistant (AR) microbes and genes. The impact of AR microbes and genes in fermented foods has far-reaching implications, such as potential effects on human health, repercussions in the food industry, and environmental consequences. An in-depth analysis of AR microbes and genes in fermented foods, including dairy products, fermented fruits and vegetables, meat products, and beverages, would provide insights into the extent and ramifications of the issue with these foods. Therefore, this review systematically presents the status of AR in fermented foods, with a particular focus on AR bacteria and genes within this category of food products. The review also highlights the complexities of AR in fermented foods, emphasizing the role of bacterial adaptation during the fermentation process and the dynamics of bacterial gene transfer. Various factors contributing to AR microbes and genes are brought into focus, including intrinsic resistance among bacteria in fermented foods and the potential risk of contamination with pathogenic bacteria. Moreover, this review presents a range of mitigation strategies, from the development of novel antimicrobials to advances in fermentation technology and regulatory control. This comprehensive perspective on the intricate interplay between AR and fermented food will potentially pave the way for more targeted research and mitigation strategies in this critical area. Full article
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14 pages, 1171 KiB  
Article
Valorisation of Waste Bread for the Production of Yeast Biomass by Yarrowia lipolytica Bioreactor Fermentation
by Erdem Carsanba, Bilal Agirman, Seraphim Papanikolaou, Patrick Fickers and Huseyin Erten
Fermentation 2023, 9(7), 687; https://doi.org/10.3390/fermentation9070687 - 21 Jul 2023
Cited by 1 | Viewed by 1365
Abstract
The increase in the wastage of bread, representing 12.5 million tons per year, causes ecological problems, such as the production of methane and CO2, when that waste bread (WB) is improperly managed. To reduce this ecological footprint, a more sustainable system [...] Read more.
The increase in the wastage of bread, representing 12.5 million tons per year, causes ecological problems, such as the production of methane and CO2, when that waste bread (WB) is improperly managed. To reduce this ecological footprint, a more sustainable system of WB management must be set up. Based on its chemical composition, WB has a high potential to be used as feedstock for microbial growth and conversion into value-added bio products. The microbial valorisation of WB is a novel biotechnological approach to upgrading a waste into a renewable feedstock for bio-based industry, thus favouring the circular economy concept. Based on this, the aim of this study was to test WB as a feedstock for biomass production by Yarrowia lipolytica, which can be considered as a promising supplement for animal and human dietary products. The enzymatic hydrolysis of WB was primarily optimized for large-scale production in a bioreactor. The biomass production of Y. lipolytica strain K57 on WB hydrolysate-based media in batch bioreactor culture was then investigated. As a result, a very high starch to glucose conversion yield of 97% was obtained throughout optimised hydrolysis. At the end of 47 h of batch culture, a biomass higher than 62 g/L, specific growth rate of 0.37 h−1 and biomass yield of 0.45 g/g were achieved from a WB hydrolysate. Therefore, this study demonstrates that WB hydrolysate has a promising potential to be used as a feedstock for biomass production by Y. lipolytica strain K57 for food and animal diet applications. Full article
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25 pages, 4743 KiB  
Article
Aroma Formation and Dynamic Changes during Sichuan Black Tea Processing by GC–MS-Based Metabolomics
by Bin Jiang, Liran Yang, Xueping Luo, Rongyan Huang, Wenwen Jiao, Xiaoxue Zhong, Lixia Li, Qi Wang, Mingli Liu and Kunyi Liu
Fermentation 2023, 9(7), 686; https://doi.org/10.3390/fermentation9070686 - 21 Jul 2023
Cited by 3 | Viewed by 1303
Abstract
Sichuan black tea (SCBT) is well known for its pleasant sweet and citrus-like aroma. However, the origin of this distinctive aroma remains unknown. Herein, the aroma characteristics of SCBT during processing were comprehensively investigated by sensory evaluation, gas chromatography–mass spectrometry, and [...] Read more.
Sichuan black tea (SCBT) is well known for its pleasant sweet and citrus-like aroma. However, the origin of this distinctive aroma remains unknown. Herein, the aroma characteristics of SCBT during processing were comprehensively investigated by sensory evaluation, gas chromatography–mass spectrometry, and odor activity value (OAV). A total of 764 volatile compounds were identified and grouped into 16 categories. Notably, terpenoids, heterocyclic compounds, and esters comprised 19.35%, 16.34%, and 16.08% of total volatile compounds produced during processing, respectively. Moreover, the fermentation and second drying stages exhibited the most striking variations, with 99 and 123 volatile compounds being significantly altered. In addition, the OAV analysis led to the identification of 17 volatile compounds as key differential volatile compounds (DVCs): these included citronellol, linalool, p-cymene, (E)-linalool oxide (furanoid), etc. Among them, (3Z)-3,7-dimethylocta-1,3,6-triene and D-limonene that exhibited a grassy aroma decreased during processing, while linalool and p-cymene that had a sweet and citrus aroma increased. Thus, based on a correlation between characteristic aroma data and descriptive sensory analysis data, linalool and p-cymene were identified as the primary volatiles responsible for the sweet and citrus-like aroma. In conclusion, this study improves our understanding of the components and formation mechanism of the sweet and citrus-like aroma of SCBT. Full article
(This article belongs to the Special Issue Flavor and Aroma in the Fermented Food)
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13 pages, 1835 KiB  
Article
Investigating the Anaerobic Digestion of Water Hyacinth (Eichhornia crassipes) Sourced from Hartbeespoort Dam in South Africa
by Trevor M. Simbayi, Charles Rashama, Ayo A. Awosusi, Rosina Nkuna, Riann Christian and Tonderayi S. Matambo
Fermentation 2023, 9(7), 685; https://doi.org/10.3390/fermentation9070685 - 20 Jul 2023
Viewed by 1457
Abstract
The biodegradability of water hyacinth for biogas and biofertilizer production was studied under mesophilic conditions. The effects of water hyacinth pretreatments were also included in this investigation. It was found that water hyacinth has a low biodegradability of 27% when monodigested, while in [...] Read more.
The biodegradability of water hyacinth for biogas and biofertilizer production was studied under mesophilic conditions. The effects of water hyacinth pretreatments were also included in this investigation. It was found that water hyacinth has a low biodegradability of 27% when monodigested, while in a 3:1 ratio with cow manure, the biodegradability increases to 46%. At this elevated biodegradability, the water hyacinth biomethane potential was 185 LCH4/kgVS, while that of cow manure was 216 LCH4/kgVS. The Gompertz kinetic model had superior parameters than the logistic model for most of the water hyacinth–cow manure combined substrate digestion. Based on the Gompertz model, the lag phase and daily maximum methane production rate were 5.5 days and 22.9 mL/day, respectively, for the 3:1 codigestion (R2 of 0.99). These values were 6.7 days and 15.2 mL/day, respectively, in the case of water hyacinth monodigestion (R2 = 0.996). The dominant microbial species detected in the digestates were Bacteroidetes and Proteobacteria. A few microbial species were indigenous to water hyacinth, but more diverse consortia, which are key to efficient substrate biodegradation, came from cow manure. The digestate contained ammonium nitrogen at 68 mg/kg with phosphorous and potassium at 73 and 424 mg/kg, respectively. Nitrogen was lower but phosphorous and potassium were comparable to previously studied digestates of other substrates. Only water hyacinth pretreated by aerobic composting was proven to unlock a higher methane yield that matched the 3:1 codigestion with cow manure. Other pretreatments induced better biodegradation performance than that observed in untreated water hyacinth but these improvements were not as good as that of the 3:1 codigestion scheme. It was concluded that water hyacinth sourced from the Hartbeespoort Dam could be treated by anaerobic digestion to recover biogas and biofertilizer. However, more experiments are required to fully understand and harness the optimisation opportunities available in applying this technology to manage water hyacinths. Full article
(This article belongs to the Special Issue Modeling Methods for Fermentation Processes)
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16 pages, 2284 KiB  
Article
Selenocysteine Formation by Enterococcus faecium ABMC-05 Follows a Mechanism That Is Not Dependent on Genes selA and selD but on Gene cysK
by Meyli Claudia Escobar-Ramírez, Gabriela Mariana Rodríguez-Serrano, Eduardo Zúñiga-León, Mario Adolfo García-Montes, Emmanuel Pérez-Escalante and Luis Guillermo González-Olivares
Fermentation 2023, 9(7), 684; https://doi.org/10.3390/fermentation9070684 - 20 Jul 2023
Cited by 1 | Viewed by 908
Abstract
Lactic acid bacteria (LAB) resist sodium selenite of concentrations greater than 100 mg/L in fermentation media. Selenium affects the growth rate, but once the microorganism absorbs selenium, this element is converted through a complex mechanism into selenocysteine and then into a selenoprotein structure. [...] Read more.
Lactic acid bacteria (LAB) resist sodium selenite of concentrations greater than 100 mg/L in fermentation media. Selenium affects the growth rate, but once the microorganism absorbs selenium, this element is converted through a complex mechanism into selenocysteine and then into a selenoprotein structure. This study verified the presence of selenocysteine in Enterococcus faecium ABMC-05. The microorganism was cultivated in a medium enriched with a minimum inhibitory concentration of sodium selenite (184 mg/L). The concentration of selenium absorbed and the bioconversion into selenocysteine were determined by inductively coupled plasma optical emission spectrometry (ICP-OES) and reverse-phase high-performance chromatography (RP-HPLC), respectively. The presence of the selD, selA, and cysK genes was determined by amplifying the 16S rDNA through polymerase chain reaction (PCR). The microorganism accumulated inorganic selenium, and part was transformed into selenocysteine. The growth curves were atypical for a lactic acid bacterium with a stationary phase greater than 70 h. Determining the genetic expression showed only the presence of the cysK gene and the absence of the selD and the selA genes. The results demonstrate that this microorganism produces selenocysteine through a mechanism independent of the SelA and SelD pathways in contrast to other LAB. Full article
(This article belongs to the Section Microbial Metabolism, Physiology & Genetics)
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13 pages, 3782 KiB  
Article
Characteristics of a Recombinant Lentinula edodes Ferulic Acid Esterase and Its Adverse Effects on In Vitro Fermentation of Wheat Straw
by Xiangyu Zhang, Xiaowen Lei, Kehui Ouyang, Wenjing Zhang, Chanjuan Liu, Yanjiao Li, Qinghua Qiu, Yitian Zang, Mingren Qu, Ke Pan and Xianghui Zhao
Fermentation 2023, 9(7), 683; https://doi.org/10.3390/fermentation9070683 - 20 Jul 2023
Viewed by 766
Abstract
Ferulic acid esterases belong to the category of carboxylesterases and possess the capability to enzymatically break down hemicellulose within lignocellulosic substances, thereby liberating ferulic acid. A ferulic acid esterase from Lentinula edodes (LeFae) was expressed using Pichia pastoris, and its characterization and [...] Read more.
Ferulic acid esterases belong to the category of carboxylesterases and possess the capability to enzymatically break down hemicellulose within lignocellulosic substances, thereby liberating ferulic acid. A ferulic acid esterase from Lentinula edodes (LeFae) was expressed using Pichia pastoris, and its characterization and effects on the in vitro fermentation of wheat straw were investigated in this study. The optimal pH and temperature for LeFae were pH 7.0 and 60 °C, respectively. LeFae exhibited a broad temperature and pH adaptability (>60% of the maximum activity at pH 4.0–7.0 and 40–70 °C) and excellent thermal stability. The activity of LeFae was increased by 30.3% with a dosage of Tween 20 at 0.25% (v/v) and exhibited satisfactory resistance to Mn2+ and sodium dodecyl sulfate. LeFae released ferulic acid from wheat straw and exhibited an obvious synergistic effect with cellulase during wheat straw hydrolysis. LeFae severely inhibited the microbial fermentation of wheat straw and reduced the in vitro dry matter digestibility, total volatile fatty acid yield, and 16S rDNA copy numbers of Ruminococcus flavefaciens by 9.6%, 9.9 mM, and 40.1%, respectively. It also increased pH and the concentration of soluble phenols during wheat straw fermentation. Pretreating wheat straw with LeFae did not affect the microbial fermentation of wheat straw but resulted in the leaching of more dissolving sugars. The current results showed that although LeFae can cooperate with cellulase to promote the hydrolysis of wheat straw, its adverse effect on rumen microorganisms when directly fed to ruminants is a problem worthy of consideration. Full article
(This article belongs to the Section Microbial Metabolism, Physiology & Genetics)
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17 pages, 1356 KiB  
Article
Evaluation of Chlamydomonas reinhardtii Microalgae as a Sustainable Feed Supplement and Fishmeal Substitute in Aquaculture with a Positive Impact on Human Nutrition
by Randa M. Darwish, Kieran James Magee, Mohamed A. Gedi, Ardeshir Farmanfarmaian, Abdelrahman S. Zaky, Iain Young and David A. Gray
Fermentation 2023, 9(7), 682; https://doi.org/10.3390/fermentation9070682 - 20 Jul 2023
Viewed by 1937
Abstract
Currently, there is an urgent need for the growing aquaculture sector to rely on sustainable ingredients which can achieve optimal growth while maintaining fish’s nutritional value (especially omega-3 fatty acid content) for human consumption. Here, C. reinhardtii biomass was substituted for fishmeal in [...] Read more.
Currently, there is an urgent need for the growing aquaculture sector to rely on sustainable ingredients which can achieve optimal growth while maintaining fish’s nutritional value (especially omega-3 fatty acid content) for human consumption. Here, C. reinhardtii biomass was substituted for fishmeal in zebrafish (Danio rerio) diets in wild-type and mutant (Casper) strains. Four isonitrogenous (46% cp), isocaloric (19–21 MJ/kg DW) diets were prepared with C. reinhardtii replacing 10% (C10), 20% (C20), and 50% (C50) of the fishmeal component of the diet formulation. Over 8 weeks of feeding trials, the zebrafish showed a significant growth improvement when fed C10, C20, and C50 compared with the control (no C. reinhardtii), with C20 giving the best performance in terms of growth, feed conversion ratio (FCR), and specific growth rate (SGR). Interestingly, C. reinhardtii in the diet increased the levels of linolenic acid (C18:3 n-3) and hexadecatrienoic acid (C16: 4-n-3) (p ≤ 0.05) in the zebrafish. Yellow pigmentation, which was shown to be lutein, was observed in eggs and zebrafish flesh for fish fed a diet containing C. reinhardtii. Moreover, the zebrafish assimilated β-carotene from C. reinhardtii and converted it to vitamin A. Overall, while replacing 20% of fishmen in the zebrafish’s diet with C. reinhardtii biomass offers the best results, replacement with only 10% showed a significant benefit for the zebrafish. Furthermore, replacing fishmeal with 50% C. reinhardtii is still possible and beneficial, and C. reinhardtii whole cells are digestible by zebrafish, thus demonstrating that C. reinhardtii not only has the potential to serve as a feed supplement but that it can also act as a feed substitute once the production cost of microalgae becomes competitive. Full article
(This article belongs to the Section Industrial Fermentation)
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12 pages, 2902 KiB  
Article
Mathematical Modeling of Nitrification in Mixed Cultures: Insights into Nitrite-Oxidizing Bacteria Growth and Ammonia Starvation Effect
by Georgios Manthos, Leila Abbaszadeh, Dimitris Zagklis and Michael Kornaros
Fermentation 2023, 9(7), 681; https://doi.org/10.3390/fermentation9070681 - 20 Jul 2023
Viewed by 1226
Abstract
Nitrification, a crucial process in wastewater treatment, involves the conversion of ammonium nitrogen to nitrate nitrogen through the sequential activities of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB). In the present study, a comprehensive mathematical model was developed to describe the nitrification process [...] Read more.
Nitrification, a crucial process in wastewater treatment, involves the conversion of ammonium nitrogen to nitrate nitrogen through the sequential activities of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB). In the present study, a comprehensive mathematical model was developed to describe the nitrification process in mixed cultures involving isolated NOB and starved AOB. The growth equation for NOB was divided into anabolism and catabolism, elucidating the key substrates driving their metabolic activities. Considering the ammonia starvation effect, a single cell-based model was developed to capture the mass transfer phenomena across the AOB cell membrane. This addition allowed for a more accurate representation of the biological dynamics during starvation conditions. The model’s accuracy was tested using experimental data that was not used in the model calibration step. The prediction’s coefficient of determination (R2) was estimated at 0.9. By providing insights into the intricate mechanisms underlying nitrification, this model contributes to the advancement of sustainable wastewater treatment practices. Full article
(This article belongs to the Special Issue Fermentation Processes: Modeling, Optimization and Control)
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14 pages, 2002 KiB  
Article
Autochthonous Microbes to Produce Ligurian Taggiasca Olives (Imperia, Liguria, NW Italy) in Brine
by Grazia Cecchi, Simone Di Piazza, Ester Rosa, Furio De Vecchis, Milena Sara Silvagno, Junio Valerio Rombi, Micaela Tiso and Mirca Zotti
Fermentation 2023, 9(7), 680; https://doi.org/10.3390/fermentation9070680 - 19 Jul 2023
Viewed by 839
Abstract
Table olives are considered high-quality food, and Italy has a wealth of varieties and typical features that are truly unique in the world (about eighty cultivars of table olives or dual-purpose olives, four of which are protected by the protected designation of origin—PDO), [...] Read more.
Table olives are considered high-quality food, and Italy has a wealth of varieties and typical features that are truly unique in the world (about eighty cultivars of table olives or dual-purpose olives, four of which are protected by the protected designation of origin—PDO), and it is the second largest European consumer, behind Spain. The Taggiasca olive does not have a PDO, but it is very appreciated not only in the region of production (Liguria), but also in all the Italian regions and abroad. Autochthonous microbes (bacteria, yeasts, and filamentous fungi) are essential in the fermentative processes for brine olive production. However, these microbial communities that colonised the olive drupes are affected by the environmental conditions and the fermentation treatments. Hence the importance of studying and comparing olive microbes from different farms and investigating the relationships between bacteria, yeasts, and filamentous fungi to speed up the deamarisation process. Our results showed that yeasts are dominant relative to lactobacteria in all three brines studied, and Wickerhamomyces anomalus was the most performant fungus for the oleuropein degradation. The latter represents the best candidate for the realisation of a microbial starter. Full article
(This article belongs to the Special Issue Development and Application of Starter Cultures)
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17 pages, 4948 KiB  
Article
Enhanced CO2 Reduction by Electron Shuttle Molecules via Coupling Different Electron Transport Processes in Microbial Electrosynthesis
by Jie Zhang, He Liu, Yan Zhang, Bo Fu, Chao Zhang, Minhua Cui, Ping Wu and Chongjun Chen
Fermentation 2023, 9(7), 679; https://doi.org/10.3390/fermentation9070679 - 19 Jul 2023
Cited by 2 | Viewed by 1146
Abstract
Electron shuttling molecules (ESMs) have been proven to accelerate the electron transfer from the electrode to the electroactive microorganism in microbial electrosynthesis (MES) for higher CO2 reduction or chemical production rate. However, the microbial electron acceptors of electroactive microorganisms and their responses [...] Read more.
Electron shuttling molecules (ESMs) have been proven to accelerate the electron transfer from the electrode to the electroactive microorganism in microbial electrosynthesis (MES) for higher CO2 reduction or chemical production rate. However, the microbial electron acceptors of electroactive microorganisms and their responses to different electron shuttling molecules in MES were still unknown. In this study, three kinds of ESMs, e.g., riboflavin (B2), methyl viologen (MV) and neutral red (NR) were applied in the MES for acetate production to explore the mechanism of different ESMs on microbial interactions. The acetate concentrations were 41% and 51% higher than that of the control in B2 and NR addition. The acetogens relative abundances of control, B2, MV and NR were 0.29%, 5.68%, 22.78% and 42.89%, respectively. The microbial function profile of the microbial community on the biocathodes indicated that the performance of acetate production was more closely related to the expression of electron transport. The B2 was coupled with the NADH complex and hydrogenase, while MV and NR were coupled with the Rnf complex to support electron transfer and energy conversion via various electron transfer pathways. The study revealed that the ESMs coupled with different electron transport complexes of microorganisms to achieve electron transfer, resulting in product changes. Full article
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16 pages, 1981 KiB  
Article
Biofuel Production from Mango and Orange Peel and Tapioca Shells by Fermentation Using Consortium of Bacteria: Agricultural and Food Waste Valorization
by Tamilselvan Vinotha, Narendrakumar Umamaheswari, Jeganathan Pandiyan, Khalid A. Al-Ghanim, Marcello Nicoletti and Marimuthu Govindarajan
Fermentation 2023, 9(7), 678; https://doi.org/10.3390/fermentation9070678 - 19 Jul 2023
Viewed by 2181
Abstract
Lignocellulosic substrates are considered to be crucial substrates for the production of biofuels. The main objective of the study is to attempt to produce bioethanol using bio-wastes such as mango peels, orange peels, and tapioca shells as renewable sources by employing three bacteria [...] Read more.
Lignocellulosic substrates are considered to be crucial substrates for the production of biofuels. The main objective of the study is to attempt to produce bioethanol using bio-wastes such as mango peels, orange peels, and tapioca shells as renewable sources by employing three bacteria viz., Enterobacter cloacae (ICBP1), Pseudomonas aeruginosa (ICBP7), and Bacillus cereus (ICBP15), which were chosen to produce cellulase enzymes using the submerged fermentation method, which is a novel method for the production of bioethanol. The “zone of clearance” in bacterial growth on CMC agar plates determined the choice. The mixed culture infected units produced a more reduced sugar, i.e., the presence of aldehyde and ketones except sucrose. At 72 h, greater than 41.0 ± 0.48 mL and 0.83 ± 0.07% of ethanol was recovered. This contrasts with the reduced quantities at 24 and 48 h. SDS-PAGE examination showed that the three cellulose-producing bacterial strains (ICPB1, ICPB7, and ICPB15) had enzyme molecular weights of 80–100, 20–30, and 14–20 kDa, respectively, compared to the other 17 isolates. Fourier-transform infrared (FTIR) spectroscopy was used to estimate the bioethanol. The spectrum bands from 1700 to 1800 cm−1 showed bioethanol’s unique absorption characteristics, and GC-MS confirmed 31.38% ethanol. The findings of the research demonstrate that the utilization of fermentation technology, specifically employing microbes, to produce bioethanol from bio-wastes such as fruits and vegetables has the potential to address the worldwide fuel energy requirements. Full article
(This article belongs to the Special Issue Advanced Research in Biomass and Waste Valorization)
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17 pages, 1449 KiB  
Article
Comprehensive Changes in Nutrient Constituents and Antioxidant Activity during Food Processing of Isoflavone-Enriched Soybean Leaf by Mycelia of Tricholoma matsutake
by Du-Yong Cho, Hee-Yul Lee, Jong-Bin Jeong, Ji-Ho Lee, Ga-Young Lee, Mu-Yeon Jang, Jin-Hwan Lee, Ji-Hyun Lee, Md. Azizul Haque and Kye-Man Cho
Fermentation 2023, 9(7), 677; https://doi.org/10.3390/fermentation9070677 - 18 Jul 2023
Cited by 1 | Viewed by 1038
Abstract
We studied the changes induced in pH, acidity, brix, reducing sugar, soluble protein, nutritional components, primary metabolites, and antioxidant activities of isoflavone-enriched soybean leaf during the different stages involved in Tricholoma matsutake mycelia fermenting. We found that total fatty acid contents increased sequentially [...] Read more.
We studied the changes induced in pH, acidity, brix, reducing sugar, soluble protein, nutritional components, primary metabolites, and antioxidant activities of isoflavone-enriched soybean leaf during the different stages involved in Tricholoma matsutake mycelia fermenting. We found that total fatty acid contents increased sequentially in dried soybean leaf, sterilized soybean leaf, and fermented soybean leaf (413.8, 420.3, and 909.4 mg/100 g, respectively). Particularly, linoleic acid content was 5-fold higher in the fermented soybean leaf than in the previous stages. The total free amino acid contents were decreased with progressing processing stages (2389.71, 1860.90, and 1434.25 mg/100 g). However, glutamic acid and lysine contents were highest in fermented soybean leaves. Total mineral contents increased with progressing processing stages (40.30, 41.72, and 55.32 mg/100 g). Water-soluble vitamins, riboflavin, and niacin were about 26-fold and 2.6-fold higher, respectively, in fermented soybean leaf. Comprehensive data analysis of primary metabolites detected changes in a total of 28 metabolites, including, amino acids, organic acids, carbohydrates, and fatty acid metabolites. Antioxidant activities were measured by 2,2-diphenyl-1-picrylhydrazyl, 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid), and hydroxyl radical scavenging activities and ferric-reducing antioxidant power. Overall, the antioxidant activities increased with progressing processing stages. Thus, we show that T. matsutake mycelia fermented isoflavone-enriched soybean leaf products have excellent nutritional value. Full article
(This article belongs to the Section Fermentation for Food and Beverages)
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17 pages, 1546 KiB  
Article
Effect of Different Vinification Techniques on the Concentration of Volatile Aroma Compounds and Sensory Profile of Malvazija Istarska Wines
by Sanja Radeka, Ena Bestulić, Sara Rossi, Fumica Orbanić, Marijan Bubola, Tomislav Plavša, Igor Lukić and Ana Jeromel
Fermentation 2023, 9(7), 676; https://doi.org/10.3390/fermentation9070676 - 18 Jul 2023
Cited by 1 | Viewed by 1262
Abstract
The majority of chemical compounds that contribute to varietal aroma originate from grape skin. To investigate the differences between volatile aroma compounds when different maceration conditions are applied, a total of six vinification treatments were carried out on Malvazija istarska (Vitis vinifera [...] Read more.
The majority of chemical compounds that contribute to varietal aroma originate from grape skin. To investigate the differences between volatile aroma compounds when different maceration conditions are applied, a total of six vinification treatments were carried out on Malvazija istarska (Vitis vinifera L.) variety, non-maceration control treatment (C), pre-fermentative two days cryomaceration treatment at 8 °C (CRYO), seven days maceration treatment at 16 °C (M7), 14 days maceration treatment at 16 °C (M14), and prolonged post-fermentative maceration treatments at 16 °C for 21 day (M21) and 42 days (M42). Wines were subjected to GC/MS and sensory analysis. Obtained results showed that prolonged post-fermentative maceration treatments contained the highest concentration of total volatile aroma compounds, precisely monoterpenes, alcohols, and other esters. Contrary, C and CRYO wines resulted in highest concentration of ethyl and acetate esters, and fatty acids. In addition, sensory analysis showed that longer maceration treatment wines (M14, M21, M42) were characterized by more aroma complexity, varietal flowery typicity, pronounced fruitiness, with accentuated dried fruit, moderate honey, and herbal notes. Obtained results can provide valuable information to producers when choosing an appropriate vinification technique based on the desired wine style which may lead to a further diversification of white wine market. Full article
(This article belongs to the Special Issue Quality and Sensory Analysis of Fermented Products)
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13 pages, 684 KiB  
Article
Effects of Formic Acid and Lactic Acid Bacteria on the Fermentation Products, Bacterial Community Diversity and Predictive Functional Characteristics of Perennial Ryegrass Silage in Karst Regions
by Yao Lei, Xueying Fan, Maoya Li, Yulian Chen, Ping Li, Yixiao Xie, Yulong Zheng, Hong Sun, Chunmei Wang, Rui Dong, Chao Chen and Qiming Cheng
Fermentation 2023, 9(7), 675; https://doi.org/10.3390/fermentation9070675 - 18 Jul 2023
Viewed by 986
Abstract
The effects of additives on perennial ryegrass (Lolium perenne L., LP) silage’s metabolites, microbial diversity and microbial metabolic pathways have been less studied in karst areas. This experiment sought to ascertain the impact of formic acid (F) and lactic acid bacteria (LAB) [...] Read more.
The effects of additives on perennial ryegrass (Lolium perenne L., LP) silage’s metabolites, microbial diversity and microbial metabolic pathways have been less studied in karst areas. This experiment sought to ascertain the impact of formic acid (F) and lactic acid bacteria (LAB) preparations introduced in karst locations on the fermentation products of LP silage, the makeup of bacterial population and the projected functional characteristics. The experiment proceeded as follows: (1) for the CK treatment, 5 mL kg−1 fresh weight (FW) of distilled water was added; (2) for the F treatment (88%), 5 mL kg−1 FW of formic acid was added; (3) for the L treatment, Lactobacillus plantarum was mixed with Lactobacillus brucei at 2 × 107 cfu/g FW. For 7, 15 and 45 days, the silage samples were kept at room temperature (20–25 °C). On day 45, the amount of lactic acid (LA) in the silage samples was substantially higher (p < 0.05) in the F (6.56% DM) and L (6.94% DM) treatments than in the CK treatment (4.47% DM), and the F treatment also had significantly lower pH and NH3-N contents than the CK and L treatments. The concentration of lactic acid (LA) was significantly higher (p < 0.05) in the F (6.56% DM) and L (6.94% DM) treatments than in the CK treatment (4.47% DM). On day 45, the dominant genera for the F and L treatments were Lactiplantibacillus (28.78% and 20.34%), Lentilactobacillus (18.85% and 12.67%) and Secundilacillus (5.01% and 13.25%), while Hafnia-Obesumbacterium (16.94%) had a higher abundance in the CK treatment. The F and L treatments promoted microbial metabolic pathways such as “metabolism”, “genetic information processing” and “organismal systems”. They reduced other microbial metabolic pathways such as “membrane transport”, “signal transduction” and “ABC transport”. In summary, F and L can enhance the quality of LP silage in karst areas by improving the structure and function of microbial communities. Full article
(This article belongs to the Section Industrial Fermentation)
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13 pages, 1911 KiB  
Article
Effects of Pulsed Light on Mycelium Growth and Conidiation in Aspergillus oryzae
by Shangfei Lin, Hui Jiang, Qiqi Fu, Shijie Huang, Luyao Tang, Angze Li and Muqing Liu
Fermentation 2023, 9(7), 674; https://doi.org/10.3390/fermentation9070674 - 18 Jul 2023
Cited by 1 | Viewed by 1140
Abstract
Understanding how Aspergillus oryzae responds to light is critical for developing efficient light regulation strategies in the brewing and waste treatment industries. Although continuous light is known to restrict A. oryzae, little is known about A. oryzae’s sensitivity to light with [...] Read more.
Understanding how Aspergillus oryzae responds to light is critical for developing efficient light regulation strategies in the brewing and waste treatment industries. Although continuous light is known to restrict A. oryzae, little is known about A. oryzae’s sensitivity to light with photoperiod. In this study, we used pulse wave modulation (PWM) to generate nine pulsed blue light (PBL) treatments with varying peak light intensities and frequencies. The effect of PBL on A. oryzae was then compared to that of continuous blue light (CBL). Our findings showed that A. oryzae GDMCC 3.31 mycelium developed faster and produced more conidia under PBL with specific peak intensities and frequencies than under CBL treatment when the light dose and average light intensity were held constant. The colony diameter and conidia count under the two PBL treatments (PL-20_40%_1 Hz and PL-400_20%_10 kHz) were 1.13 and 1.22 times greater than under the CBL treatments, respectively. This different response may be mainly attributed to A. oryzae’s adaptation to the light–dark cycles in nature. Furthermore, an interactive effect was found between peak light intensity and frequency. This work includes pulsed wave modulation as a new factor that influences the A. oryzae photoresponse and recommends it in the development of light regulation methods for fermentation. Full article
(This article belongs to the Section Microbial Metabolism, Physiology & Genetics)
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15 pages, 1060 KiB  
Article
Induced Autolysis of Engineered Yeast Residue as a Means to Simplify Downstream Processing for Valorization—A Case Study
by Joana F. Fundo, Teresa Deuchande, Daniela A. Rodrigues, Lígia L. Pimentel, Susana S. M. P. Vidigal, Luís M. Rodríguez-Alcalá, Manuela E. Pintado and Ana L. Amaro
Fermentation 2023, 9(7), 673; https://doi.org/10.3390/fermentation9070673 - 18 Jul 2023
Cited by 1 | Viewed by 1264
Abstract
The objective of this work was to study the efficiency of different autolysis processes, combining different temperatures and pH conditions, when applied to a genetically engineered yeast residue. The determination of the supernatants’ dry weight showed that the autolysis time could be reduced [...] Read more.
The objective of this work was to study the efficiency of different autolysis processes, combining different temperatures and pH conditions, when applied to a genetically engineered yeast residue. The determination of the supernatants’ dry weight showed that the autolysis time could be reduced to half, from 4 to 2 h, if the residue pH was increased from 5 to 8 at 50 °C (18.20% for 4 h and 18.70% for 2 h with a higher pH). This result allowed us to select a short autolysis time to proceed with the second part of the experiments. The application of this faster induced autolysis process enabled us to obtain supernatants with higher concentrations of relevant compounds, such as some amino acids and minerals. An increase in leucine (of around 7%), aspartic acid, valine, phenylalanine, isoleucine and serine (approximately 2%) was observed in the autolyzed samples, when compared to the untreated ones. Also, regarding minerals, the autolysis process allowed us to obtain significantly higher amounts of potassium in the treated samples’ supernatants. This work allowed the selection of a fast and low-cost induced autolysis process for synthetic biotechnology-derived spent yeast residue to attain a product rich in high-value compounds, which can be used in commercial applications, for example, as an animal feed additive. Full article
(This article belongs to the Special Issue Sustainable Development of Food Waste Biorefineries)
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13 pages, 3366 KiB  
Article
Assembly and Source of the Lithobiontic Microbial Community in Limestone
by Jin Chen, Fangbing Li, Xiangwei Zhao, Yang Wang, Limin Zhang, Feng Liu, Dan Yang, Lingbin Yan and Lifei Yu
Fermentation 2023, 9(7), 672; https://doi.org/10.3390/fermentation9070672 - 18 Jul 2023
Viewed by 898
Abstract
Due to its unique rock properties (e.g., porous nature, rough texture, and high calcium and magnesium content), limestone exhibits a high degree of bioreceptivity. However, the mechanisms underlying the establishment of limestone lithobiontic microbial communities (LLMCs) and the extent to which their composition [...] Read more.
Due to its unique rock properties (e.g., porous nature, rough texture, and high calcium and magnesium content), limestone exhibits a high degree of bioreceptivity. However, the mechanisms underlying the establishment of limestone lithobiontic microbial communities (LLMCs) and the extent to which their composition is influenced by the surrounding environment remain enigmatic. Herein, after collecting limestone sand samples, we applied various treatments: rain shelter (RS), organic acid (Oa), nutrients (Nut), inorganic acid (Ia), inorganic acid combined with nutrients (Ia+Nut15), and a blank control (CK). Subsequently, we sampled the treatments after a duration of 60 days. In addition, we collected rotted wood, concrete fences, and soil from the surrounding environment as microbial sources, while using treated limestone samples as microbial sinks. This study yields the following findings: (1) Limestone exhibits high bioreceptivity, allowing rapid microbial colonization within 60 days. Furthermore, compared to the surrounding environment, limestone can accommodate a greater diversity of microbial species. (2) The fungal and bacterial community compositions were explained by surrounding sources to the extent of 35.38% and 40.88%, respectively. The order of sources, in terms of contribution, is as follows: unknown sources > soil > rotted wood > concrete fences. (3) Higher concentrations of Ia and Ia+Nut15 treatments facilitate the colonization of fungi from the surrounding environment onto limestone while inhibiting bacterial colonization. (4) The process of establishing LLMCs is primarily driven by stochastic processes. However, Ia and Ia+Nut15 can mediate transitions in the establishment processes of bacterial communities, while Ia is solely responsible for mediating transitions in the establishment process of fungal communities. Our study offers a fresh perspective on the establishment and origins of microbial communities in limestone habitats. We believe that limestone serves as an excellent substrate for microbial colonization and holds immense potential in ecological restoration efforts within degraded karst areas. Full article
(This article belongs to the Special Issue Application of Extremophiles in Biological Degradation and Conversion)
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14 pages, 1656 KiB  
Article
Improving the Agronomic Value of Paddy Straw Using Trichoderma harzianum, Eisenia fetida and Cow Dung
by Neetu Sharma, Jagjeet Singh, Bijender Singh and Vinay Malik
Fermentation 2023, 9(7), 671; https://doi.org/10.3390/fermentation9070671 - 17 Jul 2023
Viewed by 1465
Abstract
The aim of the present study was to assess the effects of inoculation of Trichoderma harzianum, Eisenia fetida and cow dung on the physicochemical quality of paddy straw composting which was carried out for 90 days. The different treatment groups were Paddy [...] Read more.
The aim of the present study was to assess the effects of inoculation of Trichoderma harzianum, Eisenia fetida and cow dung on the physicochemical quality of paddy straw composting which was carried out for 90 days. The different treatment groups were Paddy straw (T0), Paddy straw + Cow dung (T1), Paddy straw + Cow dung + Eisenia fetida (T2), Paddy straw + Cow dung + Trichoderma harzianum (T3), Paddy straw + Cow dung + Eisenia fetida + Trichoderma harzianum (T4). The ratio of cow dung and paddy straw was 2:1. Among all treatments, T4 was identified as the best treatment for decomposing the paddy straw as it recovered the nutrients within the recommended levels of a high-quality product. The consortium of Trichoderma harzianum, Eisenia fetida and cow dung lowered the total organic carbon (TOC) and C:N ratio by 28.8% and 33.1%, respectively, at pH 6.5. The increase in N (0.87%), P (0.47%), K (2.66%), Ca (0.033%), Mg (0.056%) and Na (0.42%) was significant in T4 treatment. The micronutrients, namely Cu (47.9 ppm), Fe (1128 ppm) and Zn (500 ppm), also showed a significant increase in this treatment, i.e., T4. Therefore, results suggested that combinatorial composting by Trichoderma harzianum, Eisenia fetida and cow dung is quite promising in the decomposition of paddy straw to obtain quality compost in a short time. Furthermore, this study will help in the sustainable management of paddy straw with concomitant reduction inenvironmental pollution caused by the open burning of paddy straw. Full article
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11 pages, 1367 KiB  
Article
A Study of Key Aroma Compounds in Hurood Cheese and Their Potential Correlations with Lactic Acid Bacteria
by Yadong Wang, Hong Zeng, Yanping Cao, Shaojia Wang and Bei Wang
Fermentation 2023, 9(7), 670; https://doi.org/10.3390/fermentation9070670 - 17 Jul 2023
Cited by 1 | Viewed by 1397
Abstract
Hurood cheese (namely Hurood) is a traditional acid-coagulated cheese in China. This work investigated key aroma compounds and their potential correlations with dominant species of Hurood sampled from three distinct geographical origins. Key aroma compounds were determined according to Gas chromatography–mass spectrometry (GC–MS), [...] Read more.
Hurood cheese (namely Hurood) is a traditional acid-coagulated cheese in China. This work investigated key aroma compounds and their potential correlations with dominant species of Hurood sampled from three distinct geographical origins. Key aroma compounds were determined according to Gas chromatography–mass spectrometry (GC–MS), gas chromatography–olfactometry (GC–O), and relative odor active values (ROAVs) analyses. In addition, 16S rDNA sequencing was used to identify the dominant species. Furthermore, Pearson correlation analysis was used to determine the potential relationships between key aroma compounds and dominant species. A total of 31 key aroma compounds were identified in the Hurood samples from three regions. Lactobacillus paracasei, Lactobacillus crispatus, and Leuconostoc citreum were found to be significantly correlated with the key aroma compounds (p < 0.05) and were identified as the core species. This study shows the link between the presence of presumptive functional core microbes and the unique aroma profiles of this traditional dairy product. Full article
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19 pages, 3506 KiB  
Review
Application of Synthetic Biology Approaches to High-Yield Production of Mycosporine-like Amino Acids
by Varsha K. Singh, Sapana Jha, Palak Rana, Amit Gupta, Ashish P. Singh, Neha Kumari, Sonal Mishra, Prashant R. Singh, Jyoti Jaiswal and Rajeshwar P. Sinha
Fermentation 2023, 9(7), 669; https://doi.org/10.3390/fermentation9070669 - 17 Jul 2023
Cited by 2 | Viewed by 1970
Abstract
Ultraviolet (UV) radiation reaching the Earth’s surface is a major societal concern, and therefore, there is a significant consumer demand for cosmetics formulated to mitigate the harmful effects of UV radiation. Synthetic sunscreens being formulated to block UV penetration include inorganic metal oxide [...] Read more.
Ultraviolet (UV) radiation reaching the Earth’s surface is a major societal concern, and therefore, there is a significant consumer demand for cosmetics formulated to mitigate the harmful effects of UV radiation. Synthetic sunscreens being formulated to block UV penetration include inorganic metal oxide particles and organic filters. Lately, organic UV-absorbing compounds are manufactured from non-renewable petrochemicals and, as a result, there is a need to develop a sustainable manufacturing process for efficient, high-level production of a naturally occurring group of UV-absorbing compounds, namely mycosporine-like amino acids (MAAs), for use as a sunscreen additive to skincare products. Currently, the commercial production of MAAs for use in sunscreens is not a viable proposition due to the low yield and the lack of fermentation technology associated with native MAA-producing organisms. This review summarizes the biochemical properties of MAAs, the biosynthetic gene clusters and transcriptional regulations, the associated carbon-flux-driving processes, and the host selection and biosynthetic strategies, with the aim to expand our understanding on engineering suitable cyanobacteria for cost-effective production of natural sunscreens in future practices. Full article
(This article belongs to the Special Issue New Insights into Amino Acid Biosynthesis)
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17 pages, 3556 KiB  
Article
Isolation and Optimal Fermentation Conditions of Bacillus licheniformis SFD-Y5 for a New Douchi Fibrinolytic Enzyme Producer
by Mingjing Yao, Chunmin Ma, Xin Bian, Yang Yang, Yue Xu, Qiaoyan Wu, Xinyu Xu, Lulu Li, Na Zhang and Yanjun Tian
Fermentation 2023, 9(7), 668; https://doi.org/10.3390/fermentation9070668 - 16 Jul 2023
Cited by 1 | Viewed by 1441
Abstract
Cardiovascular disease (CVD) has become the leading cause of death, and it is critical to develop new functional foods to prevent intravascular thrombosis, the key cause of CVD. Fermented soy-based food is a good choice because of its native fibrinolytic enzyme (FE) activity. [...] Read more.
Cardiovascular disease (CVD) has become the leading cause of death, and it is critical to develop new functional foods to prevent intravascular thrombosis, the key cause of CVD. Fermented soy-based food is a good choice because of its native fibrinolytic enzyme (FE) activity. In this study, a strain that can produce a new type of fibrinolytic enzyme was selected from Chinese Douchi and identified as Bacillus licheniformis SFD-Y5 by molecular biology experiments and physiological and biochemical experiments. Single factor experiments combined with statistical experiments, including Plackett–Burman experiment, steepest ascent experiment and RSM (Box–Behnken design), were used to optimize the fermentation of FE by B. licheniformis SFD-Y5. The final FE activity was 2434.45 ± 28.49 IU/mL under optimal conditions, which is the highest FE activity produced by wild B. licheniformis so far. Further studies showed that Y5 FE is a serine metalloproteinase with good stability at alkaline pHs (pH 8.0–11.0). The results of our study could lay a foundation for the future production, molecular modification and further application in functional foods of Y5 FE. Full article
(This article belongs to the Special Issue Quality and Sensory Analysis of Fermented Products)
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17 pages, 845 KiB  
Review
Hybrid Cheeses—Supplementation of Cheese with Plant-Based Ingredients for a Tasty, Nutritious and Sustainable Food Transition
by Blandine M. L. Genet, Guillermo Eduardo Sedó Molina, Anders Peter Wätjen, Giovanni Barone, Kristian Albersten, Lilia M. Ahrné, Egon Bech Hansen and Claus H. Bang-Berthelsen
Fermentation 2023, 9(7), 667; https://doi.org/10.3390/fermentation9070667 - 15 Jul 2023
Cited by 1 | Viewed by 4380
Abstract
With increasing awareness of the impact of food on the climate, consumers are gradually changing their dietary habits towards a more plant-based diet. While acceptable products have been developed in meat analogues and non-fermented dairy products, alternative fermented dairy products such as yogurt [...] Read more.
With increasing awareness of the impact of food on the climate, consumers are gradually changing their dietary habits towards a more plant-based diet. While acceptable products have been developed in meat analogues and non-fermented dairy products, alternative fermented dairy products such as yogurt and particularly ripened hard and semi-soft cheese products are not yet satisfactory. Since the cheese category has such a broad range of flavors and applications, it has proven complicated to find plant-based sources able to mimic them in terms of texture, meltability, ripening and flavor. Moreover, plant-based dairy alternatives do not provide the same nutritional supply. New technological approaches are needed to make cheese production more sustainable, which should be integrated in the already existing conventional cheese production to ensure a fast and cost-efficient transition. This can be tackled by incorporating plant-based components into the milk matrix, creating so-called “hybrid cheeses”. This review will discuss the challenges of both animal- and plant-based cheese products and highlight how the combination of both matrices can associate the best properties of these two worlds in a hybrid product, reviewing current knowledge and development on the matter. Emphasis will be drawn to the selection and pre-processing of raw materials. Furthermore, the key challenges of removing the off-flavors and creating a desirable cheese flavor through fermentation will be discussed. Full article
(This article belongs to the Special Issue Dairy Fermentation 2.0)
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