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Fermentation, Volume 8, Issue 2 (February 2022) – 53 articles

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Reductive off-odors are among the most common wine defects. They are typically described as “rotten egg”, “cooked cabbage”, “onion”, and other undesirable aromas. Hydrogen sulfide (H2S), its derivatives (MeSH, EtSH, etc.), and reaction products are usually responsible for reductive odors and masking fruitiness in wine. These volatile sulfur compounds are normally produced during alcoholic fermentation, but they can also develop during wine storage.

The appearance of reductive off-odors after bottling is currently not well understood. In our review, we attempt to summarize the latest literature on possible precursors of H2S and its derivatives. The discussion is focused on sulfane sulfur compounds, on the hypotheses and facts of their formation, and subsequent chemical transformations during wine aging. View this paper

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20 pages, 1955 KiB  
Review
Characterization and Role of Sterols in Saccharomyces cerevisiae during White Wine Alcoholic Fermentation
by Giovana Girardi Piva, Erick Casalta, Jean-Luc Legras, Catherine Tesnière, Jean-Marie Sablayrolles, David Ferreira, Anne Ortiz-Julien, Virginie Galeote and Jean-Roch Mouret
Fermentation 2022, 8(2), 90; https://doi.org/10.3390/fermentation8020090 - 21 Feb 2022
Cited by 13 | Viewed by 7074
Abstract
Responsible for plasma membrane structure maintenance in eukaryotic organisms, sterols are essential for yeast development. The role of two sterol sources in Saccharomyces cerevisiae during wine fermentation is highlighted in this review: ergosterol (yeast sterol produced by yeast cells under aerobic conditions) and [...] Read more.
Responsible for plasma membrane structure maintenance in eukaryotic organisms, sterols are essential for yeast development. The role of two sterol sources in Saccharomyces cerevisiae during wine fermentation is highlighted in this review: ergosterol (yeast sterol produced by yeast cells under aerobic conditions) and phytosterols (plant sterols imported by yeast cells from grape musts in the absence of oxygen). These compounds are responsible for the maintenance of yeast cell viability during white wine fermentation under stress conditions, such as ethanol stress and sterol starvation, to avoid sluggish and stuck fermentations. Full article
(This article belongs to the Section Fermentation for Food and Beverages)
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12 pages, 4054 KiB  
Article
New Model High Temperature Pasting Analysis of Fermented Cassava Granules
by Ogueri Nwaiwu and Helen Onyeaka
Fermentation 2022, 8(2), 89; https://doi.org/10.3390/fermentation8020089 - 21 Feb 2022
Cited by 1 | Viewed by 2590
Abstract
Cassava is a starchy food item eaten by millions worldwide in various forms. The product has been subjected to various analysis forms, including the viscosity capacity of different flours made from the product. In this study, cassava granules (Garri) were subjected [...] Read more.
Cassava is a starchy food item eaten by millions worldwide in various forms. The product has been subjected to various analysis forms, including the viscosity capacity of different flours made from the product. In this study, cassava granules (Garri) were subjected to scanning electron microscopy (SEM) and laser diffraction particle size analysis to determine microstructure, after which the viscosity behavior was ascertained under high pressure with the new model high-temperature rapid viscosity analyzer (RVA HT 4800), which is capable of reaching a maximum of 140 °C. Viscosity comparisons were then made with the profiles obtained at 95 °C and 140 °C. The microstructure had intact starch cells and was free of extraneous materials or fungal hyphae. The granule size range was found to be 1–1800 µM. It was established that the holding, final, and setback viscosities were most affected and decreased by at least 80% when the samples were subjected to the 140 °C HT profile. The peak time at 95 °C in yellow and white Garri samples of both brands averaged nine minutes, whereas it was 5 min at 140 °C profile. The white Garri samples tolerated the high temperature better based on breakdown viscosity values and may be used for making food products that require tolerance to high temperatures. An opportunity exists to re-evaluate different Garri varieties with the new model RVA to establish behavior at very high temperatures. Full article
(This article belongs to the Special Issue Advances in Beverages, Food, Yeast and Brewing Research)
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13 pages, 1669 KiB  
Article
A CRISPR-Cas12a-Based Assay for Efficient Quantification of Lactobacillus panis in Chinese Baijiu Brewing Microbiome
by Yanfeng Liu, Mengchuang Wang, Fan Yang, Xiaolong Zhang, Jianghua Li, Guocheng Du, Li Wang and Jian Chen
Fermentation 2022, 8(2), 88; https://doi.org/10.3390/fermentation8020088 - 19 Feb 2022
Cited by 1 | Viewed by 2095
Abstract
Although the quantification of key microorganisms in fermentation microbiomes is important for monitoring and regulating fermented food production, conventionally used methods are generally time-consuming, involve complicated operations, and have a high level of equipment dependence. We developed a CRISPR-Cas12a-based quantitative Chinese Baijiu brewing [...] Read more.
Although the quantification of key microorganisms in fermentation microbiomes is important for monitoring and regulating fermented food production, conventionally used methods are generally time-consuming, involve complicated operations, and have a high level of equipment dependence. We developed a CRISPR-Cas12a-based quantitative Chinese Baijiu brewing microorganism assay (CQAOB) for Lactobacillus panis, the most important lactic acid-producing fermentative microorganism. We initially verified the feasibility of CQAOB for detecting L. panis, and then optimized the reaction parameters to enhance Cas12a detection sensitivity. The specificity of the developed method was verified via the accurate distinction of L. panis nucleic acids from those of other lactic acid bacteria. The quantitative range and detection time for L. panis were 106–109 copies/μL and 40 min, respectively. Finally, we successfully applied CQAOB for quantifying L. panis count in fermented grains. Given its rapid detection and low level of equipment dependence, CQAOB may make an important contribution to quantifying key microorganisms in brewing processes. Full article
(This article belongs to the Section Industrial Fermentation)
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12 pages, 1165 KiB  
Review
Yeast Hybrids in Brewing
by Matthew J. Winans
Fermentation 2022, 8(2), 87; https://doi.org/10.3390/fermentation8020087 - 18 Feb 2022
Cited by 1 | Viewed by 3590
Abstract
Microbiology has long been a keystone in fermentation, and innovative yeast molecular biotechnology continues to represent a fruitful frontier in brewing science. Consequently, modern understanding of brewer’s yeast has undergone significant refinement over the last few decades. This publication presents a condensed summation [...] Read more.
Microbiology has long been a keystone in fermentation, and innovative yeast molecular biotechnology continues to represent a fruitful frontier in brewing science. Consequently, modern understanding of brewer’s yeast has undergone significant refinement over the last few decades. This publication presents a condensed summation of Saccharomyces species dynamics with an emphasis on the relationship between; traditional Saccharomyces cerevisiae ale yeast, S. pastorianus interspecific hybrids used in lager production, and novel hybrid yeast progress. Moreover, introgression from other Saccharomyces species is briefly addressed. The unique history of Saccharomyces cerevisiae and Saccharomyces hybrids is exemplified by recent genomic sequencing studies aimed at categorizing brewing strains through phylogeny and redefining Saccharomyces species boundaries. Phylogenetic investigations highlight the genomic diversity of Saccharomyces cerevisiae ale strains long known to brewers for their fermentation characteristics and phenotypes. The discovery of genomic contributions from interspecific Saccharomyces species into the genome of S. cerevisiae strains is ever more apparent with increasing research investigating the hybrid nature of modern industrial and historical fermentation yeast. Full article
(This article belongs to the Special Issue Yeast Biotechnology 5.0)
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10 pages, 4511 KiB  
Article
Effects of Mulberry Branch and Leaves Silage on Microbial Community, Rumen Fermentation Characteristics, and Milk Yield in Lactating Dairy Cows
by Yan Li, Jiaqi Wang, Jie Mei, Lingxia Huang and Hongyun Liu
Fermentation 2022, 8(2), 86; https://doi.org/10.3390/fermentation8020086 - 18 Feb 2022
Cited by 6 | Viewed by 2734
Abstract
This study investigated the effects of mulberry branch and leaves (MBL) silage on milk yield, ruminal fermentation, and bacteria composition in dairy cows. Thirty-six mid-lactation cows were selected and randomly allocated into three groups. The control group (C) was fed on a total [...] Read more.
This study investigated the effects of mulberry branch and leaves (MBL) silage on milk yield, ruminal fermentation, and bacteria composition in dairy cows. Thirty-six mid-lactation cows were selected and randomly allocated into three groups. The control group (C) was fed on a total mixed ratio (TMR) diet, while the experimental groups were fed on TMR supplemented with 5% (L) and 10% (H) MBL silage. The experiment lasted for eight weeks, including two weeks of adaption. The results showed that Group H had an increased milk yield, milk fat content (p < 0.05), and 4% feed conversion ratio (p = 0.10). In addition, rumen propionic acid was significantly increased (p < 0.05), while acetate/propionate was significantly decreased (p < 0.05) in the high MBL silage group. The microbiome analysis showed that Bacteroides, Firmicutes, and Proteobacteria were the predominant phyla. Compared with Group C, the abundance of Bacteroides was significantly decreased (p < 0.01), while the Firmicutes and Proteobacteria were increased but not significantly different in Groups L and H. Prevotella was significantly decreased (p < 0.05) in the MBL silage groups, and Succinivibrionaceae_UCG-001 was increased in Group H. The correlation analysis showed that eight bacterial species belonging to Firmicutes were positively correlated with propionic acid. However, four bacterial species belonging to the Bacteroides group were negatively correlated with propionic acid. In conclusion, feed supplementation with about 5–10% of MBL silage could modulate the rumen microbiota and fermentation, and increase the abundance of fiber-digesting, propionic acid synthesis and milk fat-related microorganisms, thus improving milk yield in dairy cows. Full article
(This article belongs to the Section Microbial Metabolism, Physiology & Genetics)
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10 pages, 1917 KiB  
Article
Adaptation of Ancient Techniques to Recreate ‘Wines’ and ‘Beverages’ Using Withered Grapes of Muscat of Alexandria
by Mkrtich Harutyunyan, Renato Viana, Joana Granja-Soares, Miguel Martins, Henrique Ribeiro and Manuel Malfeito-Ferreira
Fermentation 2022, 8(2), 85; https://doi.org/10.3390/fermentation8020085 - 17 Feb 2022
Cited by 4 | Viewed by 2776
Abstract
The production of wines using ancient techniques is a present trend with commercial interest among consumers valorising their historical background. Therefore, the objective of the present work was to recreate wines and piquettes produced from dehydrated grapes, vinified according to the techniques described [...] Read more.
The production of wines using ancient techniques is a present trend with commercial interest among consumers valorising their historical background. Therefore, the objective of the present work was to recreate wines and piquettes produced from dehydrated grapes, vinified according to the techniques described in classical Roman agricultural manuals. Muscat of Alexandria grapes were harvested and subjected to greenhouse drying under ambient temperature for 7 days, during the 2020 and 2021 harvests. When weight loss was approximately 30%, grapes were processed according to different protocols, including a rehydration step using saltwater or white wine (2020 harvest). Fermentation was conducted with the addition of commercial yeast without sulphur dioxide supplementation. The piquettes were obtained from the pressed pomaces diluted with water solution (5 g/L tartaric acid). The 2020 wines showed alcoholic content and residual sugar ranging from 14.8 to 17.0% (v/v), and 0.8 g/L to 18 g/L, respectively. Volatile acidity was less than 1 g/L (as acetic acid) in all wines, except for the fermentation of crushed grapes alone, which yielded 2.3 g/L volatile acidity. The fermentation of dehydrated crushed grapes in the semi-industrial trial run in the harvest of 2021 yielded 1.1 g/L volatile acidity. The piquettes analysis showed ethanol ranging from 10.2% (v/v) to 16.0% (v/v), reducing substances less than 2 g/L and volatile acidity less than 0.8 g/L. Overall, the physicochemical analysis showed that it was possible to recreate ancient winemaking techniques that may be further improved to produce commercially and legally acceptable wines. Full article
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21 pages, 1960 KiB  
Review
Converting Sugars into Cannabinoids—The State-of-the-Art of Heterologous Production in Microorganisms
by Gabriel Rodrigues Favero, Gilberto Vinícius de Melo Pereira, Júlio Cesar de Carvalho, Dão Pedro de Carvalho Neto and Carlos Ricardo Soccol
Fermentation 2022, 8(2), 84; https://doi.org/10.3390/fermentation8020084 - 17 Feb 2022
Cited by 7 | Viewed by 9687
Abstract
The legal cannabis market worldwide is facing new challenges regarding innovation in the production of cannabinoid-based drugs. The usual cannabinoid production involves growing Cannabis sativa L. outdoor or in dedicated indoor growing facilities, followed by isolation and purification steps. This process is limited [...] Read more.
The legal cannabis market worldwide is facing new challenges regarding innovation in the production of cannabinoid-based drugs. The usual cannabinoid production involves growing Cannabis sativa L. outdoor or in dedicated indoor growing facilities, followed by isolation and purification steps. This process is limited by the growth cycles of the plant, where the cannabinoid content can deeply vary from each harvest. A game change approach that does not involve growing a single plant has gained the attention of the industry: cannabinoids fermentation. From recombinant yeasts and bacteria, researchers are able to reproduce the biosynthetic pathway to generate cannabinoids, such as (-)-Δ9-tetrahydrocannabinol (Δ9-THC), cannabidiol (CBD), and (-)-Δ9-tetrahydrocannabivarin (Δ9-THCV). This approach avoids pesticides, and natural resources such as water, land, and energy are reduced. Compared to growing cannabis, fermentation is a much faster process, although its limitation regarding the phytochemical broad range of molecules naturally present in cannabis. So far, there is not a consolidated process for this brand-new approach, being an emerging and promising concept for countries in which cultivation of Cannabis sativa L. is illegal. This survey discusses the techniques and microorganisms already established to accomplish the task and those yet in seeing for the future, exploring upsides and limitations about metabolic pathways, toxicity, and downstream recovery of cannabinoids throughout heterologous production. Therapeutic potential applications of cannabinoids and in silico methodology toward optimization of metabolic pathways are also explored. Moreover, conceptual downstream analysis is proposed to illustrate the recovery and purification of cannabinoids through the fermentation process, and a patent landscape is presented to provide the state-of-the-art of the transfer of knowledge from the scientific sphere to the industrial application. Full article
(This article belongs to the Special Issue Yeast Biotechnology 5.0)
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9 pages, 1790 KiB  
Article
Comparative Investigations on Different β-Glucosidase Surrogate Substrates
by Felix Marcel Rainer Graf and Markus Buchhaupt
Fermentation 2022, 8(2), 83; https://doi.org/10.3390/fermentation8020083 - 16 Feb 2022
Cited by 3 | Viewed by 2483
Abstract
β-glucosidases are hydrolyzing enzymes which can release many aroma-active compounds from their glycoside form. Several yeasts produce these enzymes and thus are applied during the wine production process. To be able to test specific organisms for the presence of β-glucosidases and to investigate [...] Read more.
β-glucosidases are hydrolyzing enzymes which can release many aroma-active compounds from their glycoside form. Several yeasts produce these enzymes and thus are applied during the wine production process. To be able to test specific organisms for the presence of β-glucosidases and to investigate this enzyme activity, four main surrogate substrates have been described. The properties and applicability of these compounds, named arbutin (hydroquinone-β-D-glucopyranoside), esculin (6-O-(-D-glucosyl)aesculetin), 4-nitrophenyl-β-D-glucopyranoside (pNPG) and 4-methylumbelliferyl-β-D-glucopyranoside (4-MUG), are discussed after comparing their advantages and disadvantages. Although all four substrates were found suitable for photometric assays, 4-MUG has proven to be most appropriate due to high sensitivity, high robustness and simple processing. Furthermore, the investigation of β-glucosidase product accumulation is described, which could be used to give indications about β-glucosidase localization. Full article
(This article belongs to the Special Issue Yeast Aroma)
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18 pages, 1660 KiB  
Article
Modeling and Simulation of Batch Sugarcane Alcoholic Fermentation Using the Metabolic Model
by Renam Luis Acorsi, Matheus Yuri Gritzenco De Giovanni, José Eduardo Olivo and Cid Marcos Gonçalves Andrade
Fermentation 2022, 8(2), 82; https://doi.org/10.3390/fermentation8020082 - 16 Feb 2022
Cited by 2 | Viewed by 2487
Abstract
The present work sought to implement a model different from the more traditional ones for the fermentation process of ethanol production by the action of the fungus Saccharomyces cerevisiae, using a relevant metabolic network based on the glycolytic Embden–Meyerhof–Parnas route, also [...] Read more.
The present work sought to implement a model different from the more traditional ones for the fermentation process of ethanol production by the action of the fungus Saccharomyces cerevisiae, using a relevant metabolic network based on the glycolytic Embden–Meyerhof–Parnas route, also called “EMP”. We developed two models to represent this phenomenon. In the first model, we used the simple and unbranched EMP route, with a constant concentration of microorganisms throughout the process and glucose as the whole substrate. We called this first model “SR”, regarding the Portuguese name “sem ramificações”, which means “no branches”. We developed the second model by simply adding some branches to the SR model. We called this model “CR”, regarding the Portuguese name “com ramificações”, which means “with branches”. Both models were implemented in MATLABTM software considering a constant temperature equal to 32 °C, similar to that practiced in sugar and ethanol plants, and a wide range of substrate concentrations, ranging from 30 to 100 g/L, and all the enzymes necessary for fermentation were already expressed in the cells so all the enzymes showed a constant concentration throughout the fermentation. The addition of common branches to the EMP route resulted in a considerable improvement in the results, especially predicting ethanol production closer to what we saw experimentally. Therefore, the results obtained are promising, making adjustments consistent with experimental data, meaning that all the models proposed here are a good basis for the development of future metabolic models of discontinuous fermentative processes. Full article
(This article belongs to the Section Fermentation Process Design)
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11 pages, 1816 KiB  
Article
Effect of Sea Salt and Taro Waste on Fungal Mortierella alpina Cultivation for Arachidonic Acid-Rich Lipid Production
by Yen-Hui Chen, Chang-Chng Ong and Ting-Yao Lin
Fermentation 2022, 8(2), 81; https://doi.org/10.3390/fermentation8020081 - 16 Feb 2022
Cited by 4 | Viewed by 1963
Abstract
Arachidonic acid (ARA), an important polyunsaturated fatty acid (PUFA), acts as a precursor for eicosanoid hormones, such as prostaglandins, leukotrienes and other biological substances in human and animal bodies. Mortierella alpina is considered to be a potential strain for ARA production. Using agricultural [...] Read more.
Arachidonic acid (ARA), an important polyunsaturated fatty acid (PUFA), acts as a precursor for eicosanoid hormones, such as prostaglandins, leukotrienes and other biological substances in human and animal bodies. Mortierella alpina is considered to be a potential strain for ARA production. Using agricultural waste as a substrate for microbial fermentation could achieve biorefinery concepts, and sea water utilization of the cultivation process could help to conserve fresh water resources. The objectives of this study were to find a potential M. alpina strain for ARA production, to investigate the tolerance of salinity and to evaluate the feasibility of the taro waste hydrolysate for M. alpina cultivation. The result showed that M. alpina FU30797 had the highest lipid content (25.97%) and ARA ratio (34.60%) among three strains. Furthermore, there was no significant difference between 0 and 10 g/L of sea salt solution on the biomass concentration and lipid content of M. alpina FU30797. The acidic hydrolysate and enzymatic hydrolysate of taro peel waste (TPW) were both utilized as culture substrates by M. alpina FU30797; however, the substrate up-take rate and lipid content in the TPW enzymatic hydrolysate cultivation were 292.33 mg/L-h and 30.68%, respectively, which are higher than those in acidic hydrolysate cultivation, and the ARA ratio was 33.05% in the enzymatic hydrolysate cultivation. From fed-batch cultivation in the bioreactor, the lipid content and ARA ratio reached 36.97% and 46.04%, respectively. In summary, the results from this project could potentially provide useful information for developing the PUFA-ARA bioprocess by using M. alpina. Full article
(This article belongs to the Special Issue Food Wastes: Feedstock for Value-Added Products: 3rd Edition)
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12 pages, 281 KiB  
Article
Dietary Brewer Grain Meal with Multienzymes Supplementation Affects Growth Performance, Gut Health, and Antioxidative Status of Weaning Pigs
by Waewaree Boontiam, Jinsu Hong and Yoo-Yong Kim
Fermentation 2022, 8(2), 80; https://doi.org/10.3390/fermentation8020080 - 16 Feb 2022
Cited by 2 | Viewed by 1695
Abstract
We conducted a 28-day feeding study on 80 weaning pigs [(Landrace × Large White) × Duroc] to determine the effects of dietary inclusion with brewer’s grain meal (BGM) and multienzymes on their growth, intestinal health, and antioxidative status. Piglets were grouped by sex [...] Read more.
We conducted a 28-day feeding study on 80 weaning pigs [(Landrace × Large White) × Duroc] to determine the effects of dietary inclusion with brewer’s grain meal (BGM) and multienzymes on their growth, intestinal health, and antioxidative status. Piglets were grouped by sex and initial BW and assigned to 20 pens with four pigs each. Treatments were a corn–soybean meal-based diet with either 0.1% multienzyme addition (PC) or without (NC), and two BGM compositions fortified with 0.1% multienzyme: 10% (BGM10) and 20% (BGM20). The overall body weight, average daily weight gain, and weight gain:feed ratio were significantly greater in pigs fed BGM20 than those fed the NC diet (p < 0.05). Moreover, the BGM diets significantly increased the digestibility of total ash and ether extract, glucose, total protein, immunoglobulin A, total antioxidant capacity, superoxide dismutase, heart and small intestine weights, villus height: crypt depth ratio (VH/CD), and Lactobacillus spp. count compared with the NC diet (p < 0.05). The diarrheal rate, blood urea nitrogen, malondialdehyde, duodenal crypt depth, and Salmonella spp. count were reduced in pigs fed the BGM-supplemented diet than those fed the NC diet (p < 0.05). The diarrheal rate (p = 0.010), ether extract digestibility (p = 0.044), total protein (p = 0.044), and duodenal villus height and VH/CD (p = 0.003 and p = 0.002, respectively) decreased quadratically with the increase in BGM supplementation. Overall, diets containing up to 20% BGM with multienzyme addition improved the nutrient utilization and intestinal health in weaning pigs by suppressing pathogenic bacterial growth without compromising the overall growth of the pigs. Full article
(This article belongs to the Section Fermentation for Food and Beverages)
22 pages, 2320 KiB  
Article
Production of Exopolysaccharides by Cultivation of Halotolerant Bacillus atrophaeus BU4 in Glucose- and Xylose-Based Synthetic Media and in Hydrolysates of Quinoa Stalks
by Diego Chambi, Jenny Lundqvist, Erik Nygren, Luis Romero-Soto, Katherine Marin, András Gorzsás, Mattias Hedenström, Markus Carlborg, Markus Broström, Ola Sundman, Cristhian Carrasco, Leif J. Jönsson and Carlos Martín
Fermentation 2022, 8(2), 79; https://doi.org/10.3390/fermentation8020079 - 14 Feb 2022
Cited by 4 | Viewed by 3571
Abstract
A halotolerant, exopolysaccharide-producing bacterium isolated from the Salar de Uyuni salt flat in Bolivia was identified as Bacillus atrophaeus using next-generation sequencing. Comparisons indicate that the genome most likely (p-value: 0.0024) belongs to a subspecies previously not represented in the database. [...] Read more.
A halotolerant, exopolysaccharide-producing bacterium isolated from the Salar de Uyuni salt flat in Bolivia was identified as Bacillus atrophaeus using next-generation sequencing. Comparisons indicate that the genome most likely (p-value: 0.0024) belongs to a subspecies previously not represented in the database. The growth of the bacterial strain and its ability to produce exopolysaccharides (EPS) in synthetic media with glucose or xylose as carbon sources, and in hydrolysates of quinoa stalks, was investigated. The strain grew well in all synthetic media, but the growth in glucose was better than that in xylose. Sugar consumption was better when initial concentrations were low. The growth was good in enzymatically produced cellulosic hydrolysates but was inhibited in hemicellulosic hydrolysates produced using hydrothermal pretreatment. The EPS yields were up to 0.064 g/g on initial glucose and 0.047 g/g on initial xylose, and was higher in media with relatively low sugar concentrations. The EPS was isolated and purified by a sequential procedure including centrifugation, cold ethanol precipitation, trichloroacetic acid treatment, dialysis, and freeze-drying. Glucose and mannose were the main sugars identified in hydrolyzed EPS. The EPS was characterized by size-exclusion chromatography, Fourier-transform infrared (FTIR) spectroscopy, heteronuclear single-quantum coherence nuclear magnetic resonance (HSQC NMR) spectroscopy, scanning electron microscopy, X-ray diffraction, and thermogravimetric analysis. No major differences were elucidated between EPS resulting from cultivations in glucose- or-xylose-based synthetic media, while some divergences with regard to molecular-weight averages and FTIR and HSQC NMR spectra were detected for EPS from hydrolysate-based media. Full article
(This article belongs to the Special Issue Food Wastes: Feedstock for Value-Added Products: 3rd Edition)
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15 pages, 319 KiB  
Article
Development of a Taxon-Specific Real-Time PCR Method Targeting the Bacillus subtilis Group to Strengthen the Control of Genetically Modified Bacteria in Fermentation Products
by Marie-Alice Fraiture, Andrea Gobbo, Nina Papazova and Nancy H. C. Roosens
Fermentation 2022, 8(2), 78; https://doi.org/10.3390/fermentation8020078 - 12 Feb 2022
Cited by 3 | Viewed by 2595
Abstract
Most of the bacteria that are used to produce fermentation products, such as enzymes, additives and flavorings, belong to the Bacillus subtilis group. Recently, unexpected contaminations with unauthorized genetically modified (GM) bacteria (viable cells and associated DNA) that were carrying antimicrobial resistance (AMR) [...] Read more.
Most of the bacteria that are used to produce fermentation products, such as enzymes, additives and flavorings, belong to the Bacillus subtilis group. Recently, unexpected contaminations with unauthorized genetically modified (GM) bacteria (viable cells and associated DNA) that were carrying antimicrobial resistance (AMR) genes was noticed in several microbial fermentation products that have been commercialized on the food and feed market. These contaminations consisted of GM Bacillus species belonging to the B. subtilis group. In order to screen for the potential presence of such contaminations, in this study we have developed a new real-time PCR method targeting the B. subtilis group, including B. subtilis, B. licheniformis, B. amyloliquefaciens and B. velezensis. The method’s performance was successfully assessed as specific and sensitive, complying with the Minimum Performance Requirements for Analytical Methods of GMO Testing that is used as a standard by the GMO enforcement laboratories. The method’s applicability was also tested on 25 commercial microbial fermentation products. In addition, this method was developed to be compatible with the PCR-based strategy that was recently developed for the detection of unauthorized GM bacteria. This taxon-specific method allows the strengthening of the set of screening markers that are targeting key sequences that are frequently found in GM bacteria (AMR genes and shuttle vector), reinforcing control over the food and feed chain in order to guarantee its safety and traceability. Full article
(This article belongs to the Special Issue Contamination of Fermentation Systems and Methods of Control)
14 pages, 3412 KiB  
Article
Antimicrobial Activity of Zymomonas mobilis Is Related to Its Aerobic Catabolism and Acid Resistance
by Reinis Rutkis, Zane Ļaša, Marta Rubina, Rita Ščerbaka, Gints Kalniņš, Jānis Bogans and Uldis Kalnenieks
Fermentation 2022, 8(2), 77; https://doi.org/10.3390/fermentation8020077 - 12 Feb 2022
Cited by 1 | Viewed by 2753
Abstract
Zymomonas mobilis is an ethanologenic, facultatively anaerobic alpha-proteobacterium, known for its inhibitory effect on the growth of a wide variety of microorganisms. This property might be interesting for the design of novel antimicrobials, yet it has negative implications for biotechnology, as it hinders [...] Read more.
Zymomonas mobilis is an ethanologenic, facultatively anaerobic alpha-proteobacterium, known for its inhibitory effect on the growth of a wide variety of microorganisms. This property might be interesting for the design of novel antimicrobials, yet it has negative implications for biotechnology, as it hinders the use of Z. mobilis as a producer microorganism in cocultivation. So far, the chemical nature of its inhibitory compound(s) has not been established. In the present study, we demonstrate that the putative inhibitor is a low-molecular-weight (below 3 kDa), thermostable compound, resistant to protease treatment, which is synthesized under aerobic conditions in Z. mobilis strains via the active respiratory chain. It is also synthesized by aerated nongrowing, glucose-consuming cells in the presence of chloramphenicol, thus ruling out its bacteriocin-like peptide nature. The inhibitory activity is pH-dependent and strongly correlated with the accumulation of propionate and acetate in the culture medium. Although, in Z. mobilis, the synthesis pathways of these acids still need to be identified, the acid production depends on respiration, and is much less pronounced in the non-respiring mutant strain, which shows low inhibitory activity. We conclude that propionate and acetate play a central role in the antimicrobial effects of Z. mobilis, which itself is known to bear high resistance to organic acids. Full article
(This article belongs to the Special Issue Bioconversion of Lignocellulosic Materials to Value-Added Products)
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25 pages, 901 KiB  
Review
Chitosan Production by Fungi: Current State of Knowledge, Future Opportunities and Constraints
by Silvia Crognale, Cristina Russo, Maurizio Petruccioli and Alessandro D’Annibale
Fermentation 2022, 8(2), 76; https://doi.org/10.3390/fermentation8020076 - 11 Feb 2022
Cited by 32 | Viewed by 7459
Abstract
Conventionally, the commercial supply of chitin and chitosan relies on shellfish wastes as the extraction sources. However, the fungal sources constitute a valuable option, especially for biomedical and pharmaceutical applications, due to the batch-to-batch unsteady properties of chitin and chitosan from conventional ones. [...] Read more.
Conventionally, the commercial supply of chitin and chitosan relies on shellfish wastes as the extraction sources. However, the fungal sources constitute a valuable option, especially for biomedical and pharmaceutical applications, due to the batch-to-batch unsteady properties of chitin and chitosan from conventional ones. Fungal production of these glycans is not affected by seasonality enables accurate process control and, consequently, more uniform properties of the obtained product. Moreover, liquid and solid production media often are derived from wastes, thus enabling the application of circular economy criteria and improving the process economics. The present review deals with fungal chitosan production processes focusing on waste-oriented and integrated production processes. In doing so, contrary to other reviews that used a genus-specific approach for organizing the available information, the present one bases the discussion on the bioprocess typology. Finally, the main process parameters affecting chitosan production and their interactions are critically discussed. Full article
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12 pages, 3531 KiB  
Article
Inhibition Activity of Plantaricin Q7 Produced by Lactobacillus plantarum Q7 against Listeria monocytogenes and Its Biofilm
by Yinxue Liu, Yushan Bu, Jianxun Li, Yisuo Liu, Ao Liu, Pimin Gong, Tongjie Liu, Lanwei Zhang, Shumei Wang and Huaxi Yi
Fermentation 2022, 8(2), 75; https://doi.org/10.3390/fermentation8020075 - 10 Feb 2022
Cited by 4 | Viewed by 2006
Abstract
Plantaricin Q7 is a broad-spectrum antimicrobial peptide produced by Lactobacillus plantarum Q7. The effects of plantaricin Q7 on Listeria monocytogenes and its biofilm were investigated. The results showed that plantaricin Q7 changed the cell membrane permeability and integrity of Listeria monocytogenes significantly. The [...] Read more.
Plantaricin Q7 is a broad-spectrum antimicrobial peptide produced by Lactobacillus plantarum Q7. The effects of plantaricin Q7 on Listeria monocytogenes and its biofilm were investigated. The results showed that plantaricin Q7 changed the cell membrane permeability and integrity of Listeria monocytogenes significantly. The extracellular lactate dehydrogenase activity increased from 156.74 U/L to 497.62 U/L, and the K+ concentration was increased rapidly from 0.02 g/L to 0.09 g/L. Furthermore, the flagellum motility of Listeria monocytogenes reduced and the relative adhesion rate decreased about 30% after treatment with plantaricin Q7. Meanwhile, the morphology and structure of Listeria monocytogenes cell and biofilm were damaged. These findings suggested that plantaricin Q7 exhibited significant inhibitory effects on not only Listeria monocytogenes cell but also its biofilm, which might be used as a natural and effective biological preservative for food storage. Full article
(This article belongs to the Section Microbial Metabolism, Physiology & Genetics)
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11 pages, 18308 KiB  
Article
Probiotics-Derived Extracellular Vesicles Protect Oxidative Stress against H2O2 Induction in Placental Cells
by Le-Ming Wang, Bao-Hong Lee, Chih-Yao Hou, Wei-Hsuan Hsu and Chen-Jei Tai
Fermentation 2022, 8(2), 74; https://doi.org/10.3390/fermentation8020074 - 10 Feb 2022
Cited by 5 | Viewed by 2464
Abstract
(1) Background: The microbial phase in the vaginal environment has been found to regulate the physiological activity of host cells. Studies have demonstrated that abnormal microbial growth in the vagina and a significant reduction in the proportion of lactic acid bacteria promote the [...] Read more.
(1) Background: The microbial phase in the vaginal environment has been found to regulate the physiological activity of host cells. Studies have demonstrated that abnormal microbial growth in the vagina and a significant reduction in the proportion of lactic acid bacteria promote the occurrence of spontaneous preterm birth (sPTB). However, the contributing mechanism remains unknown. (2) Methods: This study uses extracellular vesicles (EVs) secreted by the probiotic Lactobacillus crispatus, commonly found in the vagina, to explore their potential to attenuate placental cells caused by oxidative stress induction. (3) Results: We found that L. crispatus-derived EVs improved Akt phosphorylation and attenuated both cell senescence and death in placental cells caused by oxidative stress induction. In addition, L. crispatus-derived EVs enhanced the resistance to H2O2 induction mediated by increasing mitochondrial fusion. (4) Conclusion: This is the first study to demonstrate that L. crispatus in the vagina can not only regulate the physiological functions of placental cells through the delivery of L. crispatus-EVs but also reduce cell senescence. As cell senescence is related to the occurrence of sPTB, these results indicate that maintaining the population of L. crispatus in the vaginal environment should be an adjuvant treatment strategy to avoid sPTB. Full article
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11 pages, 2020 KiB  
Article
Assessment of Lemon Juice Starter Addition on Secondary Fermented Soy Sauce
by Yun-Hsi Chang, GiGi Chin Wen Lim, Ju-Yun Chien, Lu-Sheng Hsieh, Shinn-Dar Wu and Jhih-Ying Ciou
Fermentation 2022, 8(2), 73; https://doi.org/10.3390/fermentation8020073 - 09 Feb 2022
Viewed by 3789
Abstract
Soy sauce is one of the most popular ingredients for delicious cuisines across the world, and it is made via various fermentation processes using wheat and soybeans. The purpose of this study was to add a lemon juice starter into secondary fermentation soy [...] Read more.
Soy sauce is one of the most popular ingredients for delicious cuisines across the world, and it is made via various fermentation processes using wheat and soybeans. The purpose of this study was to add a lemon juice starter into secondary fermentation soy sauce to produce a new flavor of soy sauce to meet current health awareness and innovation market trends. The results showed that the lactic acid bacteria of the A group (soy sauce/starter culture ratio of 3:1) gradually decreased from 9.89 to 8.32 log CFU/mL by the seventh day, and then to 5.39 log CFU/mL by the 30th day, while they were not detected by the 60th day. Meanwhile, those of the B group (soy sauce/starter culture ratio of 1:1) showed a decrease from 10.39 to 8.58 log CFU/mL by the seventh day, and then to 5.39 log CFU/mL by the 30th day and 4.43 log CFU/mL by the 60th day, while they were not detected by the 90th day. As for yeast, the A group showed a decrease from 10.83 to 9.29 log CFU/mL (or 10.25 to 9.27 log CFU/mL for the B group) by the seventh day. Yeasts were not detected after 30 days in either the A or B group. The acidity and salinity of the lemon-flavored sauce was maintained after secondary fermentation. Sensory evaluation showed that the soy sauce with a lemon juice starter was accepted by consumers and obtained a better result than commercial soy sauce. In conclusion, secondary fermentation with starters contributes to the flavor quality of sauce products. Fruit juice is adjustable in terms of the acidity and salinity of the soy sauce and produces good flavor after secondary fermentation whenever it acts as a starter. The fact that customers favored the innovative lemon-flavored soy sauce indicates that this study is on the right trend. Full article
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15 pages, 2172 KiB  
Article
Bio-Fermentation Improved Rumen Fermentation and Decreased Methane Concentration of Rice Straw by Altering the Particle-Attached Microbial Community
by Yao Xu, Min Aung, Zhanying Sun, Yaqi Zhou, Yanfen Cheng, Lizhuang Hao, Varijakshapanicker Padmakumar and Weiyun Zhu
Fermentation 2022, 8(2), 72; https://doi.org/10.3390/fermentation8020072 - 08 Feb 2022
Cited by 5 | Viewed by 2483
Abstract
Bio-fermentation technology has been successfully developed for ensiling rice straw; however, its effects on the particle-attached microbial community remains unknown. Therefore, rice straw (RS) and bio-fermented rice straw (BFRS) were used as substrates for in vitro rumen fermentation to investigate the effect of [...] Read more.
Bio-fermentation technology has been successfully developed for ensiling rice straw; however, its effects on the particle-attached microbial community remains unknown. Therefore, rice straw (RS) and bio-fermented rice straw (BFRS) were used as substrates for in vitro rumen fermentation to investigate the effect of bio-fermentation on particle-attached microbial community, as well as their effects on gas and methane production, fermentation products, and fiber degradation. Our results have shown that total gas production, fiber degradation, and in vitro fermentation products were significantly higher (p < 0.05) for the BFRS than the RS, while methane concentration in total gas volume was significantly lower (p < 0.05) for the BFRS than RS. Linear discriminant effect size (LefSe) analysis revealed that the relative abundance of the phyla Bacteroidetes, Fibrobacteres, Proteobacteria, and Lantisphaerae, as well as the genera Fibrobacter, Saccharofermentans, and [Eubacterium] ruminantium groups in the tightly attached bacterial community, was significantly higher (p < 0.05) for the BFRS than the RS, whereas other microbial communities did not change. Thus, bio-fermentation altered the tightly attached bacterial community, thereby improving gas production, fiber degradation, and fermentation products. Furthermore, bio-fermentation reduced methane concentration in total gas volume without affecting the archaeal community. Full article
(This article belongs to the Special Issue Silage Fermentation)
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12 pages, 2106 KiB  
Article
Aspergillus-Derived Cellulase Preparation Exhibits Prebiotic-like Effects on Gut Microbiota in Rats
by Yongshou Yang, Thanutchaporn Kumrungsee, Norihisa Kato, Shinji Fukuda, Manabu Kuroda and Shotaro Yamaguchi
Fermentation 2022, 8(2), 71; https://doi.org/10.3390/fermentation8020071 - 08 Feb 2022
Cited by 4 | Viewed by 2031
Abstract
Aspergillus-derived cellulase, which is involved in the production of Aspergillus-fermented foods, has been employed in the food and animal feed industries. However, the effect of dietary Aspergillus cellulase on health is poorly understood. Previously, we discovered that supplemental Aspergillus-derived protease [...] Read more.
Aspergillus-derived cellulase, which is involved in the production of Aspergillus-fermented foods, has been employed in the food and animal feed industries. However, the effect of dietary Aspergillus cellulase on health is poorly understood. Previously, we discovered that supplemental Aspergillus-derived protease and lipase preparations had substantial bifidogenic effects on rats fed a high-fat diet. Therefore, this study reports on the effects of a 0.1% dietary Aspergillus-derived cellulase preparation (CEL) on the gut microbiota of rats fed a high-fat diet. Gene sequencing analysis of 16S rRNA revealed that CEL treatment markedly affected the microbiota profiles of the cecal contents (p < 0.05). Notably, CEL markedly increased the relative abundance (RA) of typical probiotics, such as Bifidobacterium and Lactobacillus, at the genus level (28- and 5-fold, respectively, p < 0.05). Similarly, at the family level, CEL treatment significantly increased the RA of Bifidobacteriaceae and Lactobacillaceae (p < 0.05). Furthermore, CEL increased the RA of other genera, such as Collinsella and Enterococcus, but decreased the RA of Oscillospira, Dorea and Coprobacillus (p < 0.05). The effects on these genera are similar to those reported for typical prebiotic oligosaccharides. Overall, this study demonstrates the prebiotic-like effects of dietary CEL by significantly increasing Bifidobacterium and Lactobacillus abundance. Full article
(This article belongs to the Special Issue Fermented Foods and Microbes Related to Health)
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15 pages, 1940 KiB  
Article
Lignocellulose Degradation and Enzymatic Hydrolysis of Soybean Incorporated Sorghum Silage Inoculated with Feruloyl-Esterase Producing Lactobacillus plantarum
by Samaila Usman, Fuhou Li, Dong An, Na Shou, Jianqiang Deng, Yixin Zhang, Xusheng Guo and Yuying Shen
Fermentation 2022, 8(2), 70; https://doi.org/10.3390/fermentation8020070 - 07 Feb 2022
Cited by 8 | Viewed by 2397
Abstract
Availability of feedstock is one of the uncertainties impeding cellulosic biofuel production, and conservation of whole crop biomass as silage is a promising method to ensure year-round feedstock availability for biofuel production. This study investigated lignocellulose degradation and subsequent enzymatic hydrolysis of a [...] Read more.
Availability of feedstock is one of the uncertainties impeding cellulosic biofuel production, and conservation of whole crop biomass as silage is a promising method to ensure year-round feedstock availability for biofuel production. This study investigated lignocellulose degradation and subsequent enzymatic hydrolysis of a 90-d sorghum silage incorporated with soybean and inoculated with Lactobacillus plantarum A1 in a three (0, 25, and 50%; soybean inclusions) by two (uninoculated and inoculated) factorial experiment. The results revealed that L. plantarum A1 inoculated silages had improved fermentation characteristics. The silages’ total N and non-fiber carbohydrate increased with L. plantarum A1 and soybean inclusion (p < 0.05). Inoculation also increased the residual water-soluble carbohydrate by 33.9% (p < 0.05). Inoculation and soybean inclusion significantly hydrolyzed the biomass’ lignocellulose, altered its morphology and microstructural matrix, increased production of ferulic acid and reduced the biomass crystallinity by 15.60% (p < 0.05). L. plantarum A1 inoculation × soybean inclusion improved glucose yield and cellulose conversion during enzymatic saccharification compared to uninoculated treatments. Therefore, incorporating soybean into sorghum silage with L. plantarum A1 inoculation enhanced fermentation quality, lignocellulose degradation and enzymatic saccharification which could serve as a sure way for sustainable year-round feedstock supply for enhanced biofuel production. Full article
(This article belongs to the Special Issue Silage Fermentation)
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19 pages, 1322 KiB  
Article
Changes in Volatile Compounds and Quality Characteristics of Salted Shrimp Paste Stored in Different Packaging Containers
by Jaksuma Pongsetkul, Soottawat Benjakul and Pakpoom Boonchuen
Fermentation 2022, 8(2), 69; https://doi.org/10.3390/fermentation8020069 - 07 Feb 2022
Cited by 7 | Viewed by 2620
Abstract
Quality changes of salted shrimp paste, one of the most popular traditional Thai fermented food ingredients, stored in different packaging containers including polypropylene containers (PP), polyethylene terephthalate containers (PET), glass jar containers (GJ) as well as LLDPE/Nylon vacuum bags (VB) at room temperature [...] Read more.
Quality changes of salted shrimp paste, one of the most popular traditional Thai fermented food ingredients, stored in different packaging containers including polypropylene containers (PP), polyethylene terephthalate containers (PET), glass jar containers (GJ) as well as LLDPE/Nylon vacuum bags (VB) at room temperature (28 ± 1 °C) for 15 months were studied. The relationship between quality attributes (i.e., volatiles, browning index (A420), biogenic amines, TBARS) and consumer acceptability as indicated by sensory scores were also investigated using principal component analysis (PCA). During storage, some desirable quality characteristics of shrimp paste were improved as indicated by the higher sensory scores of all samples when stored for 6 months, compared with the sample at day 0 (p ≤ 0.05). However, further changes in all compositions when extended storage time can conversely diminish those desirable characteristics and led to lowering consumers’ acceptability. In this study, GJ seem to be the most potential packaging for preserving original products’ quality during storage for this product since it exhibited the lower rate of quality changing than others throughout the storage. Conversely, VB exhibited unique volatiles and microbial profiles, compared with others, which led to the lowest sensory scores at all period test (p ≤ 0.05), implying that vacuum conditions may not be suitable for the storage of this product. Moreover, based on PCA results, the intensity of nitrogen-containing compounds correlated well with sensory acceptability, particularly flavor-likeness. Our study provides useful knowledge for understanding the different quality characteristics, particularly flavors, associated with different packaging containers during prolonged storage of salted shrimp paste. Full article
(This article belongs to the Special Issue Machine Learning in Fermented Food and Beverages)
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11 pages, 2002 KiB  
Article
Controlling the Formation of Foams in Broth to Promote the Co-Production of Microbial Oil and Exopolysaccharide in Fed-Batch Fermentation
by Yan-Feng Guo, Meng-Qi Wang, Yi-Lei Wang, Hong-Tao Wang and Jian-Zhong Xu
Fermentation 2022, 8(2), 68; https://doi.org/10.3390/fermentation8020068 - 07 Feb 2022
Cited by 3 | Viewed by 5481
Abstract
A large amount of foam is generated in the production of microbial oil and exopolysaccharide (EPS) by Sporidiobolus pararoseus JD-2, which causes low efficiency in fermentation. In this study, we aimed to reduce the negative effects of foams on the co-production of oil [...] Read more.
A large amount of foam is generated in the production of microbial oil and exopolysaccharide (EPS) by Sporidiobolus pararoseus JD-2, which causes low efficiency in fermentation. In this study, we aimed to reduce the negative effects of foams on the co-production of oil and EPS by controlling the formation of foams in broth. As we have found, the formation of foams is positively associated with cell growth state, air entrapment, and properties of broth. The efficient foam-control method of adding 0.03% (v/v) of the emulsified polyoxyethylene polyoxypropylene pentaerythritol ether (PPE) and feeding corn steep liquor (CSL) at 8–24 h with speed of 0.02 L/h considerably improved the fermentation performance of S. pararoseus JD-2, and significantly increased the oil and EPS concentrations by 8.7% and 12.9%, respectively. The biomass, oil, and EPS concentrations were further increased using a foam backflow device combined with adding 0.03% (v/v) of the emulsified PPE and feeding CSL at 8–24 h, which reached to 62.3 ± 1.8 g/L, 31.2 ± 0.8 g/L, and 10.9 ± 0.4 g/L, respectively. The effective strategy for controlling the formation of foams in fermentation broth reported here could be used as a technical reference for producing frothing products in fed-batch fermentation. Full article
(This article belongs to the Special Issue Applied Microorganisms and Industrial/Food Enzymes)
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19 pages, 4459 KiB  
Article
Microbial Diversity and Metabolites Dynamic of Light-Flavor Baijiu with Stacking Process
by Zhaojie Li, Yi Fan, Xiaoning Huang and Beizhong Han
Fermentation 2022, 8(2), 67; https://doi.org/10.3390/fermentation8020067 - 05 Feb 2022
Cited by 8 | Viewed by 2187
Abstract
Stacking is a widely used method of microbial enrichment in the field of fermentation and is traditionally used to promote flavor in Chinese sauce-flavor Baijiu; however, its precise mechanism is unknown. This study assessed the fermentation process of light-flavor Baijiu with the [...] Read more.
Stacking is a widely used method of microbial enrichment in the field of fermentation and is traditionally used to promote flavor in Chinese sauce-flavor Baijiu; however, its precise mechanism is unknown. This study assessed the fermentation process of light-flavor Baijiu with the simplest microbial source. After comparing differences in the microbial composition of different kinds of Daqu, a high-temperature Daqu with a microbial composition that significantly differs from light-flavor Daqu was selected for stacking. The physical and chemical indicators, microbial community composition, and metabolite profiles during the fermentation process were tracked, and the total ester content in Baiju was significantly higher with stacking than Baijiu without stacking. The dominant bacteria during stacking fermentation were Bacillus and Enterococcus, while Lactobacillus was the dominant bacteria during middle and late fermentation periods. Low levels of Lactobacillus and Pichia in Daqu were screened and enriched during the stacking process, while the glucose and acetate content significantly increased. Flavor compounds such as esters and acids were positively correlated with dominant genera such as Lactobacillus, Bacillus, and Pichia. Stacking provides microorganisms for environmental screening, which regulates the microbial community structure and produces various metabolites and precursors of flavor substances to fully saccharify and promote the production of flavor substances. Stacking during the production of light-flavor Baijiu can help regulate the fermentation process and improve Baijiu quality. Full article
(This article belongs to the Section Microbial Metabolism, Physiology & Genetics)
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14 pages, 2432 KiB  
Article
Characterization and Viability Prediction of Commercial Probiotic Supplements under Temperature and Concentration Conditioning Factors by NIR Spectroscopy
by Juan Pablo Aguinaga Bósquez, Esma Oǧuz, Aybike Cebeci, Mariem Majadi, Gabriella Kiskó, Zoltan Gillay and Zoltan Kovacs
Fermentation 2022, 8(2), 66; https://doi.org/10.3390/fermentation8020066 - 31 Jan 2022
Cited by 6 | Viewed by 5255
Abstract
The quality of probiotics has been associated with bacteria and yeast strains’ contents and their stability against conditioning factors. Near-infrared spectroscopy (NIRS), as a non-destructive, fast, real-time, and cost-effective analytical technique, can provide some advantages over more traditional food quality control methods in [...] Read more.
The quality of probiotics has been associated with bacteria and yeast strains’ contents and their stability against conditioning factors. Near-infrared spectroscopy (NIRS), as a non-destructive, fast, real-time, and cost-effective analytical technique, can provide some advantages over more traditional food quality control methods in quality evaluation. The aim of our study was to evaluate the applicability of NIRS to the characterization and viability prediction of three commercial probiotic food supplement powders containing lactic acid bacteria (LAB) subjected to concentration and temperature conditioning factors. For each probiotic, 3 different concentrations were considered, and besides normal preparation (25 °C, control), samples were subjected to heat treatment at 60 or 90 °C and left to cool down until reaching room temperature prior to further analysis. Overall, after applying chemometrics to the NIR spectra, the obtained principal component analysis-based linear discriminant analysis (PCA-LDA) classification models showed a high accuracy in both recognition and prediction. The temperature has an important impact on the discrimination of samples. According to the concentration, the best models were identified for the 90 °C temperature treatment, reaching 100% average correct classification for recognition and over 90% for prediction. However, the prediction accuracy decreased substantially at lower temperatures. For the 25 °C temperature treatment, the prediction accuracy decreased to nearly 60% for 2 of the 3 probiotics. Moreover, according to the temperature level, both the recognition and prediction accuracies were close to 100%. Additionally, the partial least square regression (PLSR) model achieved respectable values for the prediction of the colony-forming units (log CFU/g) of the probiotic samples, with a determination coefficient for prediction (R2Pr) of 0.82 and root mean square error for prediction (RMSEP) of 0.64. The results of our study show that NIRS is a fast, reliable, and promising alternative to the conventional microbiology technique for the characterization and prediction of the viability of probiotic supplement drink preparations. Full article
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19 pages, 3083 KiB  
Article
Machine Learning Algorithms for Temperature Management in the Anaerobic Digestion Process
by Senem Önen Cinar, Samet Cinar and Kerstin Kuchta
Fermentation 2022, 8(2), 65; https://doi.org/10.3390/fermentation8020065 - 30 Jan 2022
Cited by 15 | Viewed by 3957
Abstract
Process optimization is no longer an option for processes, but an obligation to survive in the market in any industry. This argument also applies to anaerobic digestion in biogas plants. The contribution of biogas plants to renewable energy can be increased through more [...] Read more.
Process optimization is no longer an option for processes, but an obligation to survive in the market in any industry. This argument also applies to anaerobic digestion in biogas plants. The contribution of biogas plants to renewable energy can be increased through more productive systems with less waste, which brings the common goal of minimizing costs and maximizing yields in processes. With the help of data science and predictive analytics, it is possible to take conventional process optimization and operational excellence methods, such as statistical process control and Six Sigma, to the next level. The more advanced the process optimization aspect, the more transparent and responsive the systems. In this study, seven different machine learning algorithms—linear regression, logistic regression, K-NN, decision trees, random forest, support vector machine (SVM) and XGBoost—were compared with laboratory results to define and predict the possible impacts of wide range temperature fluctuations on process stability. SVM provided the best accuracy with 0.93 according to the metric precision of the models calculated using the confusion matrix. Full article
(This article belongs to the Special Issue New Research on Anaerobic Digestion)
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18 pages, 4605 KiB  
Article
Production of Fumaric Acid by Rhizopus arrhizus NRRL 1526: A Simple Production Medium and the Kinetic Modelling of the Bioprocess
by Victor Martin-Dominguez, Paula I. Aleman Cabrera, Laslo Eidt, Ulf Pruesse, Anja Kuenz, Miguel Ladero and Victoria E. Santos
Fermentation 2022, 8(2), 64; https://doi.org/10.3390/fermentation8020064 - 30 Jan 2022
Cited by 6 | Viewed by 4375
Abstract
Fumaric acid is a promising monomer to obtain biomass-based polyesters and polyamides, and it is mainly produced by fungi of the Rhizopus genus in medium to high titters. The use of glucose, a main component of starchy and cellulosic food waste, as carbon [...] Read more.
Fumaric acid is a promising monomer to obtain biomass-based polyesters and polyamides, and it is mainly produced by fungi of the Rhizopus genus in medium to high titters. The use of glucose, a main component of starchy and cellulosic food waste, as carbon source, together with a low-nitrogen source concentration, is a promising route to reduce process costs. In this work, the effects of nitrogen and carbonate sources on Rhizopus arrhizus NRRL 1526 morphology and fumaric acid productivity were analysed, simplifying the traditional production broth composition. Moreover, a non-structured, non-segregated kinetic model was proposed and fitted to concentration data of all relevant components obtained in batches performed in triplicate with the selected production broth at 34 °C and 200 rpm in an orbital shaker. Full article
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57 pages, 1367 KiB  
Review
Fermentation of Cereals and Legumes: Impact on Nutritional Constituents and Nutrient Bioavailability
by Janet Adeyinka Adebo, Patrick Berka Njobeh, Sefater Gbashi, Ajibola Bamikole Oyedeji, Opeoluwa Mayowa Ogundele, Samson Adeoye Oyeyinka and Oluwafemi Ayodeji Adebo
Fermentation 2022, 8(2), 63; https://doi.org/10.3390/fermentation8020063 - 30 Jan 2022
Cited by 56 | Viewed by 13040
Abstract
Fermented food products, especially those derived from cereals and legumes are important contributors to diet diversity globally. These food items are vital to food security and significantly contribute to nutrition. Fermentation is a process that desirably modifies food constituents by increasing the palatability, [...] Read more.
Fermented food products, especially those derived from cereals and legumes are important contributors to diet diversity globally. These food items are vital to food security and significantly contribute to nutrition. Fermentation is a process that desirably modifies food constituents by increasing the palatability, organoleptic properties, bioavailability and alters nutritional constituents. This review focuses on deciphering possible mechanisms involved in the modification of nutritional constituents as well as nutrient bioavailability during the fermentation of cereals and legumes, especially those commonly consumed in developing countries. Although modifications in these constituents are dependent on inherent and available nutrients in the starting raw material, it was generally observed that fermentation increased these nutritive qualities (protein, amino acids, vitamins, fats, fatty acids, etc.) in cereals and legumes, while in a few instances, a reduction in these constituents was noted. A general reduction trend in antinutritional factors was also observed with a corresponding increase in the nutrient bioavailability and bioaccessibility. Notable mechanisms of modification include transamination or the synthesis of new compounds during the fermentation process, use of nutrients as energy sources, as well as the metabolic activity of microorganisms leading to a degradation or increase in the level of some constituents. A number of fermented products are yet to be studied and fully understood. Further research into these food products using both conventional and modern techniques are still required to provide insights into these important food groups, as well as for an overall improved food quality, enhanced nutrition and health, as well as other associated socioeconomic benefits. Full article
(This article belongs to the Special Issue Food Fermentation for Better Nutrition, Health and Sustainability)
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12 pages, 3397 KiB  
Article
Induction of Chromosomal Aneuploids from Brewery Shochu Yeast with Novel Brewery Characteristics
by Yuki Kusaba, Akira Otsuka, Huanghuang Dai, Shigeki Inaba and Hiroshi Kitagaki
Fermentation 2022, 8(2), 62; https://doi.org/10.3390/fermentation8020062 - 30 Jan 2022
Cited by 1 | Viewed by 2316
Abstract
The first development method of brewery shochu yeast focusing on chromosomal aneuploidy is reported in this study. Euploidy diploid shochu yeast S-3 was treated with a microtubule inhibitor, nocodazole, for the purpose of inducing aneuploidy. Next, 2,3,5-triphenyl tetrazolium chloride (TTC) staining and the [...] Read more.
The first development method of brewery shochu yeast focusing on chromosomal aneuploidy is reported in this study. Euploidy diploid shochu yeast S-3 was treated with a microtubule inhibitor, nocodazole, for the purpose of inducing aneuploidy. Next, 2,3,5-triphenyl tetrazolium chloride (TTC) staining and the growth rate were investigated to select aneuploids. Aneuploids were selected at a frequency of 8.2 × 10−4, which was significantly higher than that of the control group, mainly at chromosomes I, II, III, IX, XII, XIII, and XVI. The acquired aneuploids were evaluated for their metabolic and brewing characteristics. A hierarchical cluster analysis based on endogenous metabolite data discriminated euploid S-3 and aneuploids. In addition, principal-component analysis of the constituents of the broth brewed with the strains discriminated between euploid S-3 and aneuploids. Sensory evaluation of the broth brewed with euploid S-3 and aneuploids showed that it tended to differ in aroma and taste. Specific ethanol production rates of the aneuploids were not deteriorated. The method of this selection made it possible to efficiently obtain aneuploids with various brewing characteristics from brewer’s yeast, which do not correspond to genetically modified organisms. This novel breeding method focusing on chromosomal aneuploidy will facilitate the development of novel shochu yeast strains. Full article
(This article belongs to the Special Issue Advances in Beverages, Food, Yeast and Brewing Research)
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11 pages, 2727 KiB  
Article
Isolation and Characterization of Pediococcus sp. HLV1 from Fermented Idly Batter
by Harika Katepogu, Young-Jung Wee, Khalid S. Almaary, Yahya B. Elbadawi, Ramachawolran Gobinath, Suresh V. Chinni and Veeranjaneya Reddy Lebaka
Fermentation 2022, 8(2), 61; https://doi.org/10.3390/fermentation8020061 - 30 Jan 2022
Cited by 5 | Viewed by 3230
Abstract
The aim of the present study is the isolation and characterization of the lactic acid bacteria from idly batter, a traditional Indian fermented product. To achieve the aim, 10 idly batter samples were selected from different regions of Kadapa district. In the primary [...] Read more.
The aim of the present study is the isolation and characterization of the lactic acid bacteria from idly batter, a traditional Indian fermented product. To achieve the aim, 10 idly batter samples were selected from different regions of Kadapa district. In the primary isolation and screening process, 50 lactic-acid-producing bacteria were isolated, and from them, six strains were selected based on their lactic acid yielding capacity for further evaluation. The selected cultures were studied for their phenotypic characters, and all cultures were Gram positive, cocci, and catalase negative. All the six strains were tested for their growth and lactic acid production at above 35 °C, and finally, one strain that showed good growth at 50 °C was selected for further characterization. Molecular characterization by 16S rRNA gene analysis and BLAST analysis revealed 99% similarity with Pediococcus pentosaceus Ni1142. The isolated culture was named as Pediococcus sp. HLV1, and the sequence was submitted to the NCBI databank as accession number MH921241. The isolated strain is able to utilize a wide range of carbohydrate substrates including glucose, fructose, sucrose, lactose, maltose, and xylose. The major fermentation product from glucose is lactic acid. Pediococcus sp. HLV1 showed optimum growth and production of lactic acid with glucose as carbon source (10%) and yeast extract as nitrogen source (0.3%) at pH 7.0 and 40 °C. As well-known probiotic bacteria, the isolated Pediococcus spp. also showed antimicrobial activity against both Gram-positive and Gram-negative bacteria and more specifically inhibited Gram-positive Bacillus. Using the above optimal conditions, lactic acid from a fresh mango peel extract was studied, and at the end of the fermentation, 5.2% (v/v) of lactic acid was produced. In conclusion, the isolated LAB Pediococcus sp. strain HLV1 is able to grow and produce lactic acid at a high temperature (45 °C) and to survive at 50 °C. Mango peel, a by-product of mango pulp industries, can be utilized as one of the economically cheap feedstocks for industrial production of lactic acid by the Pediococcus sp. strain HLV1. Full article
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