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Fermentation
Volume 8
Issue 9
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Fermentation, Volume 8, Issue 9 (September 2022) – 53 articles

Cover Story (view full-size image): As the global population continues to grow, the demand for food would also continue to increase. Hence, resulting in unsustainable agricultural practices such as overuse of chemical fertilizers to increase productivity. This would result in degradation of soil fertility and soil compaction. This study evaluates the potential effects of seaweeds utilized as organic fertilizers to increase rice productivity. Our key findings show that SF treatment increases nutritional quality of amino acid content in rice grains and abundance of rhizosphere beneficial bacteria. Seaweeds could be considered a promising component of blue economy development in agricultural countries. View this paper
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16 pages, 330 KiB  
Article
Functional and Healthy Yogurts Fortified with Probiotics and Fruit Peel Powders
by Hafza Fasiha Zahid, Chaminda Senaka Ranadheera, Zhongxiang Fang and Said Ajlouni
Fermentation 2022, 8(9), 469; https://doi.org/10.3390/fermentation8090469 - 19 Sep 2022
Cited by 15 | Viewed by 3334
Abstract
The application of processing waste by-products along with probiotics is an interesting choice to confer potential functional aspects to food products. This study was designed to investigate the nutritional capacity of freeze-dried mango peel powder (MPP) and banana peel powder (BPP) in the [...] Read more.
The application of processing waste by-products along with probiotics is an interesting choice to confer potential functional aspects to food products. This study was designed to investigate the nutritional capacity of freeze-dried mango peel powder (MPP) and banana peel powder (BPP) in the presence of a mixture of three probiotic species (1% of each of three probiotics (Lacticaseibacillus casei (431®), Lacticaseibacillus rhamnosus (LGG®) and Bifidobacterium subsp. Lactis (Bb-12®)) as sources of additional nutrients and prebiotics in fresh and rehydrated freeze-dried (RFD) yogurts for 28 days of refrigerated storage. The net count of probiotics in yogurt fortified with MPP and BPP increased by at least 1 log CFU/g after 4 weeks of refrigerated storage. Adding fruit peel powder (FPP) significantly (p < 0.05) increased fat, ash, and protein contents in both fresh and RFD yogurts in comparison with the control yogurt. Similarly, the total phenolic contents (TPC) and antioxidant activity (AOA) was enhanced significantly (p < 0.05). The TPC reached 2.27 ± 0.18 and 2.73 ± 0.11 mg GAE/g in RFD enriched with BPP and MPP compared to a TPC of 0.31 ± 0.07 mg GAE/g in the control. Additionally, yogurt samples enriched with BPP (Y-5) and MPP (Y-6) demonstrated 12% more sugar contents than non-fortified yogurts (Y-1). Higher titratable acidity and lower pH values were also recorded in the RFD yogurt. Significant differences (p < 0.05) in the color parameters were detected in both fresh and RFD yogurts with reduced brightness (L*) and increased redness (a*) of the product. These findings demonstrated the suitability of MPP and BPP in yogurt formulations to optimize the advantages of such synbiotic products with higher availability of phenolic compounds. Full article
(This article belongs to the Special Issue Bioactivity Change in Fermented Foods)
14 pages, 3420 KiB  
Article
The Purification and Biochemical Characterization of a Weissella cibaria F1 Derived β-Mannanase for Its Use in the Preparation of Konjac Oligo-Glucomannan with Immunomodulatory Properties
by Shuo Wang, Hairui Ji, Renpeng Du, Wenxiang Ping, Jingping Ge and Dan Zhao
Fermentation 2022, 8(9), 468; https://doi.org/10.3390/fermentation8090468 - 18 Sep 2022
Cited by 3 | Viewed by 1731
Abstract
Mannanase with a molecular weight of 33.1 kDa was purified from Weissella cibaria F1. The F1 mannanase contained 289 amino acid residues and shared 70.0% similarity with mannanase from Bacillus subtilis (P55278 (MANB_BACIU)). The optimum reaction conditions of F1 mannanase were 50 °C [...] Read more.
Mannanase with a molecular weight of 33.1 kDa was purified from Weissella cibaria F1. The F1 mannanase contained 289 amino acid residues and shared 70.0% similarity with mannanase from Bacillus subtilis (P55278 (MANB_BACIU)). The optimum reaction conditions of F1 mannanase were 50 °C and pH 6.5. After incubation at pH 4.5–8.0 and 30–60 °C for 2 h, the enzyme activity remained above 60%. The effects of metal ions on mannanase enzyme activity were measured, and Mn2+, Mg2+, and Cu2+ increased enzyme activity. The Km (16.96 ± 0.01 μmol·mL−1) and Vmax (1119.05 ± 0.14 μmol·min−1) values showed that the enzyme exhibited high affinity for locust bean gum. Mannanase was used to hydrolyze konjac glucomannan to produce konjac oligo-glucomannan (KOGM). KOGM increased the proliferation and phagocytosis of RAW264.7 macrophages and enhanced nitric oxide, and cytokine production in macrophages, which showed potent immunostimulatory activity. In this study, the advantages of mannanase derived from lactic acid bacteria were utilized to expand the application of KOGM in the medical field, which is helpful to explore the broad prospects of KOGM in functional food or medicine. Full article
(This article belongs to the Section Microbial Metabolism, Physiology & Genetics)
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11 pages, 1934 KiB  
Article
Comparative Fatty Acid Compositional Profiles of Rhodotorula toruloides Haploid and Diploid Strains under Various Storage Conditions
by Yue Zhang, Rasool Kamal, Qing Li, Xue Yu, Qian Wang and Zongbao Kent Zhao
Fermentation 2022, 8(9), 467; https://doi.org/10.3390/fermentation8090467 - 18 Sep 2022
Cited by 5 | Viewed by 2314
Abstract
Microbial-based fatty acids (FAs), biofuels and oleochemicals are potential alternatives to fossil fuels and other non-renewable resources. Rhodotorula toruloides (formerly Rhodosporidium toruloides) is a basidiomycetous oleaginous yeast, and cells of the wild-type diploids can accumulate lipids to over 70 wt% on a [...] Read more.
Microbial-based fatty acids (FAs), biofuels and oleochemicals are potential alternatives to fossil fuels and other non-renewable resources. Rhodotorula toruloides (formerly Rhodosporidium toruloides) is a basidiomycetous oleaginous yeast, and cells of the wild-type diploids can accumulate lipids to over 70 wt% on a dry cell weight basis in nutrient-limited conditions. Meanwhile, several haploid strains have been applied as hosts for producing high-value fatty acid derivatives through genetic modification and metabolic engineering. However, the differences in fatty acid compositional profiles and their stability between diploid and haploid strains remain unknown in this oleaginous yeast. Here, we grew a haploid strain R. toruloides NP11 and its parental diploid strain R. toruloides CGMCC 2.1389 (4#) under identical conditions and compared the profiles in terms of cell growth, lipid production, fatty acid compositions of lipids as well as storage stability of fatty acid methyl esters (FAMEs). It was found that lipids from R. toruloides composed of fatty acids in terms of chain length ranged from short-chain FAs (C6–C9) to very long-chain FAs (VLCFAs, C20–C24) and some odd-chain FAs (C15 and C17), while long-chain fatty acids (C14–C18) were the most abundant ones. In addition, NP11 produced a little more (1 wt%) VLCFAs than that of the diploid strain 4#. Moreover, no major changes were found for FAMEs being held under varied storage conditions, suggesting that FAMEs samples were stable and robust for fatty acid compositional analysis of microbial lipids. This work revealed the fatty acid profiles of lipids from R. toruloides haploid and diploid strains, and their stability under various storage conditions. The information is valuable for reliable assessment of fatty acid compositions of lipids from oleaginous yeasts and related microbial cell factories. Full article
(This article belongs to the Special Issue Yeast, Biofuels, and Value-Added Products)
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30 pages, 2160 KiB  
Review
Recent Advances in Marine Microalgae Production: Highlighting Human Health Products from Microalgae in View of the Coronavirus Pandemic (COVID-19)
by Mohamed Ashour and Ashraf M. M. Omran
Fermentation 2022, 8(9), 466; https://doi.org/10.3390/fermentation8090466 - 18 Sep 2022
Cited by 11 | Viewed by 3998
Abstract
Blue biotechnology can greatly help solve some of the most serious social problems due to its wide biodiversity, which includes marine environments. Microalgae are important resources for human needs as an alternative to terrestrial plants because of their rich biodiversity, rapid growth, and [...] Read more.
Blue biotechnology can greatly help solve some of the most serious social problems due to its wide biodiversity, which includes marine environments. Microalgae are important resources for human needs as an alternative to terrestrial plants because of their rich biodiversity, rapid growth, and product contributions in many fields. The production scheme for microalgae biomass mainly consists of two processes: (I) the Build-Up process and (II) the Pull-Down process. The Build-Up process consists of (1) the super strain concept and (2) cultivation aspects. The Pull-Down process includes (1) harvesting and (2) drying algal biomass. In some cases, such as the manufacture of algal products, the (3) extraction of bioactive compounds is included. Microalgae have a wide range of commercial applications, such as in aquaculture, biofertilizer, bioenergy, pharmaceuticals, and functional foods, which have several industrial and academic applications around the world. The efficiency and success of biomedical products derived from microalgal biomass or its metabolites mainly depend on the technologies used in the cultivation, harvesting, drying, and extraction of microalgae bioactive molecules. The current review focuses on recent advanced technologies that enhance microalgae biomass within microalgae production schemes. Moreover, the current work highlights marine drugs and human health products derived from microalgae that can improve human immunity and reduce viral activities, especially COVID-19. Full article
(This article belongs to the Special Issue Marine-Based Biorefinery: A Path Forward to a Sustainable Future)
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17 pages, 1287 KiB  
Article
Conversion of Syngas from Entrained Flow Gasification of Biogenic Residues with Clostridium carboxidivorans and Clostridium autoethanogenum
by Anton Rückel, Anne Oppelt, Philipp Leuter, Philipp Johne, Sebastian Fendt and Dirk Weuster-Botz
Fermentation 2022, 8(9), 465; https://doi.org/10.3390/fermentation8090465 - 17 Sep 2022
Cited by 4 | Viewed by 2251
Abstract
Synthesis gas fermentation is a microbial process, which uses anaerobic bacteria to convert CO-rich gases to organic acids and alcohols and thus presents a promising technology for the sustainable production of fuels and platform chemicals from renewable sources. Clostridium carboxidivorans and Clostridium autoethanogenum [...] Read more.
Synthesis gas fermentation is a microbial process, which uses anaerobic bacteria to convert CO-rich gases to organic acids and alcohols and thus presents a promising technology for the sustainable production of fuels and platform chemicals from renewable sources. Clostridium carboxidivorans and Clostridium autoethanogenum are two acetogenic bacteria, which have shown their high potential for these processes by their high tolerance toward CO and in the production of industrially relevant products such as ethanol, 1-butanol, 1-hexanol, and 2,3-butanediol. A promising approach is the coupling of gasification of biogenic residues with a syngas fermentation process. This study investigated batch processes with C. carboxidivorans and C. autoethanogenum in fully controlled stirred-tank bioreactors and continuous gassing with biogenic syngas produced by an autothermal entrained flow gasifier on a pilot scale >1200 °C. They were then compared to the results of artificial gas mixtures of pure gases. Because the biogenic syngas contained 2459 ppm O2 from the bottling process after gasification of torrefied wood and subsequent syngas cleaning for reducing CH4, NH3, H2S, NOX, and HCN concentrations, the oxygen in the syngas was reduced to 259 ppm O2 with a Pd catalyst before entering the bioreactor. The batch process performance of C. carboxidivorans in a stirred-tank bioreactor with continuous gassing of purified biogenic syngas was identical to an artificial syngas mixture of the pure gases CO, CO2, H2, and N2 within the estimation error. The alcohol production by C. autoethanogenum was even improved with the purified biogenic syngas compared to reference batch processes with the corresponding artificial syngas mixture. Both acetogens have proven their potential for successful fermentation processes with biogenic syngas, but full carbon conversion to ethanol is challenging with the investigated biogenic syngas. Full article
(This article belongs to the Section Microbial Metabolism, Physiology & Genetics)
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20 pages, 4424 KiB  
Article
An Alternative Approach to Improve the Butanol Production Efficiency from Sweet Sorghum Stem Juice Using Immobilized Cells Combined with an In Situ Gas Stripping System
by Thanawat Thanapornsin, Pattana Laopaiboon and Lakkana Laopaiboon
Fermentation 2022, 8(9), 464; https://doi.org/10.3390/fermentation8090464 - 17 Sep 2022
Cited by 4 | Viewed by 1702
Abstract
The effects of the nitrogen source and buffers used in butanol production with Clostridium beijerinckii TISTR 1461 from sweet sorghum stem juice (SSJ) containing 60 g/L of total sugar were first studied in this paper. Among the various nitrogen sources (dried spent yeast, [...] Read more.
The effects of the nitrogen source and buffers used in butanol production with Clostridium beijerinckii TISTR 1461 from sweet sorghum stem juice (SSJ) containing 60 g/L of total sugar were first studied in this paper. Among the various nitrogen sources (dried spent yeast, urea, ammonium acetate, ammonium sulfate), urea was found to be the most suitable for butanol production. SSJ supplemented with urea (0.64 g/L) and cocktail buffers (KH2PO4, 0.5 g/L; K2HPO4, 0.5 g/L; ammonium acetate, 2.2 g/L) gave the highest butanol concentration (PB, 10.13 g/L). Then, the capability of immobilized C. beijerinckii TISTR 1461 cells for butanol fermentation was investigated. Two residual waste materials were examined as immobilized cell carriers. Bamboo chopstick pieces were more appropriate as carriers for cell immobilization than cigarette filter tips. The PB value of the immobilized cells on the bamboo chopstick pieces was ~13% higher than that on the cigarette filter tips. Using the response surface methodology (RSM), 1.9 cm bamboo chopstick pieces with a carrier loading of 1:32 (w/v) were the optimum conditions for cell immobilization for butanol production. Under these conditions, the PB value was 11.62 g/L. To improve the butanol production efficiency, a gas stripping system (GS) was connected to the fermenter. It was found that the PB (14.02 g/L) and butanol productivity (QB, 0.29 g/L·h) values improved by ~21% compared to butanol fermentation using no gas stripping. Full article
(This article belongs to the Section Microbial Metabolism, Physiology & Genetics)
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21 pages, 4148 KiB  
Article
Increasing Biomethane Production in MSW Anaerobic Digestion Process by Chemical and Thermal Pretreatment and Process Commercialization Evaluation
by Esfandiyar Naeiji, Alireza Noorpoor and Hossein Ghnavati
Fermentation 2022, 8(9), 463; https://doi.org/10.3390/fermentation8090463 - 16 Sep 2022
Cited by 1 | Viewed by 1867
Abstract
One of the methods of municipal waste disposal and energy production is anaerobic digestion. This study investigates the effect of thermal and chemical pretreatment on the anaerobic digester’s biomethane production. The optimal condition was evaluated using RSM in two modes: maximum and minimum [...] Read more.
One of the methods of municipal waste disposal and energy production is anaerobic digestion. This study investigates the effect of thermal and chemical pretreatment on the anaerobic digester’s biomethane production. The optimal condition was evaluated using RSM in two modes: maximum and minimum use of H2O2. The optimal state was obtained in the first case under 110.8 °C, 4.63% NaOH, 8% H2O2, and 111.9 °C, 4.47% NaOH, 2% H2O2 in the second case. Experimental results obtained 77%, 76.6% VS (volatile solid) reduction, and 89.1%, 88.7% SCOD (soluble chemical oxygen demand) reduction in the two optimum conditions, respectively. Experiment results were extrapolated to dry industrial digesters using a factor of 0.89% and durations including 30 days and 25 days. Then, the processes of biogas improvement were simulated. After biogas improvement, the economic analysis of the process was conducted with the definition of various scenarios. It was determined that, at current prices, pretreatment is not economically viable and that, with an increase in electricity prices to 0.09 $/kWh and 0.145 $/kWh, the digestion process with a NaOH 4.47% 112 °C pretreatment, chemical scrubbing, and digestion with NaOH 4.47% 112 °C, 2% H2O2 are sequentially economically viable. Full article
(This article belongs to the Special Issue Biofuels Production and Processing Technology 2.0)
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24 pages, 6921 KiB  
Article
Brackish and Hypersaline Lakes as Potential Reservoir for Enzymes Involved in Decomposition of Organic Materials on Frescoes
by Ioana Gomoiu, Roxana Cojoc, Robert Ruginescu, Simona Neagu, Madalin Enache, Gabriel Maria, Maria Dumbrăvician, Ioana Olteanu, Roxana Rădvan, Lucian-Cristian Ratoiu, Victoria Atanassova and Luminița Ghervase
Fermentation 2022, 8(9), 462; https://doi.org/10.3390/fermentation8090462 - 16 Sep 2022
Cited by 4 | Viewed by 1804
Abstract
This study highlights the decomposing role through the hydrolytic activities of fungi isolated from natural environments represented by brackish and hypersaline lakes in Romania. Novel strains belonging to the Penicillium, Aspergillus, and Emericellopsis genera were isolated and screened for the ability [...] Read more.
This study highlights the decomposing role through the hydrolytic activities of fungi isolated from natural environments represented by brackish and hypersaline lakes in Romania. Novel strains belonging to the Penicillium, Aspergillus, and Emericellopsis genera were isolated and screened for the ability to produce extracellular hydrolytic enzymes, i.e., proteases, lipases, amylases, cellulases, xylanases, and pectinases. According to salt requirements, they were classified as moderate halophilic and halotolerant strains. Agar plate-based assays with Tween 80, slide cultures with organic deposits, and quantitative evaluation allowed the selection of Aspergillus sp. BSL 2-2, Penicillium sp. BSL 3-2, and Emericellopsis sp. MM2 as potentially good decomposers of organic matter not only in lakes but also on deposits covering the mural paintings. Experiments performed on painted experimental models revealed that only Penicillium sp. BSL 3-2 decomposed Paraloid B72, transparent dispersion of casein, beeswax, sunflower oil, and soot. Moreover, using microscopic, spectroscopic, and imaging methods, it was proved the efficiency of Penicillium sp. BSL 3-2 for decomposition of organic deposits artificially applied on frescoes fragments. Full article
(This article belongs to the Special Issue Extremophiles—Source for Novel Biomolecules with Applied Potential)
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12 pages, 1152 KiB  
Article
In Vitro Fermentation and Degradation Characteristics of Rosemary Extract in Total Mixed Ration of Lactating Dairy Cows
by Fanlin Kong, Shuo Wang, Zhijun Cao, Yajing Wang, Shengli Li and Wei Wang
Fermentation 2022, 8(9), 461; https://doi.org/10.3390/fermentation8090461 - 15 Sep 2022
Cited by 2 | Viewed by 1752
Abstract
Rosemary extract (RE) is characterized as an antioxidant, and it has the potential to reduce methane emission and change microbial fermentation. Hence, to the extent of the evaluation of RE in ruminant nutrition, the in vitro fermentation technique was used to investigate the [...] Read more.
Rosemary extract (RE) is characterized as an antioxidant, and it has the potential to reduce methane emission and change microbial fermentation. Hence, to the extent of the evaluation of RE in ruminant nutrition, the in vitro fermentation technique was used to investigate the effects of RE on the fermentation characteristics of a total mixed ration (TMR) fed to dairy cows. Different doses of RE were added to the TMR to obtain different concentrations of antioxidants, including 0 (CON), 0.05 (LRE), and 0.10 g/kg (HRE). A total of 500 mg ground TMR was incubated in buffer solution and rumen fluid for 48 h at 39 °C. Nutrient degradability, gas production parameters, gas composition, fermentation parameters, and microbial composition were analyzed. The results showed that nutrient degradability and total volatile fatty acid concentration were not affected by the treatments. Furthermore, total methane production and proportion were depressed in a dose-dependent way. The RE increased the propionate concentration and proportion linearly and decreased the acetate concentration and proportion linearly. Finally, microbial diversity analysis showed that the richness and evenness indexes were unchanged by different treatments, while Prevotella_1 was decreased and Prevotella_7 was increased with RE supplementation. In conclusion, RE is an effective inhibitor of methane emission of microbial fermentation and changed the profile of volatile fatty acids with no disadvantageous effects on diet utilization. Full article
(This article belongs to the Special Issue Rumen Fermentation)
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23 pages, 1458 KiB  
Review
Natural Substrates and Culture Conditions to Produce Pigments from Potential Microbes in Submerged Fermentation
by Chatragadda Ramesh, V. R. Prasastha, Mekala Venkatachalam and Laurent Dufossé
Fermentation 2022, 8(9), 460; https://doi.org/10.3390/fermentation8090460 - 14 Sep 2022
Cited by 13 | Viewed by 4284
Abstract
Pigments from bacteria, fungi, yeast, cyanobacteria, and microalgae have been gaining more demand in the food, leather, and textile industries due to their natural origin and effective bioactive functions. Mass production of microbial pigments using inexpensive and ecofriendly agro-industrial residues is gaining more [...] Read more.
Pigments from bacteria, fungi, yeast, cyanobacteria, and microalgae have been gaining more demand in the food, leather, and textile industries due to their natural origin and effective bioactive functions. Mass production of microbial pigments using inexpensive and ecofriendly agro-industrial residues is gaining more demand in the current research due to their low cost, natural origin, waste utilization, and high pigment stimulating characteristics. A wide range of natural substrates has been employed in submerged fermentation as carbon and nitrogen sources to enhance the pigment production from these microorganisms to obtain the required quantity of pigments. Submerged fermentation is proven to yield more pigment when added with agro-waste residues. Hence, in this review, aspects of potential pigmented microbes such as diversity, natural substrates that stimulate more pigment production from bacteria, fungi, yeast, and a few microalgae under submerged culture conditions, pigment identification, and ecological functions are detailed for the benefit of industrial personnel, researchers, and other entrepreneurs to explore pigmented microbes for multifaceted applications. In addition, some important aspects of microbial pigments are covered herein to disseminate the knowledge. Full article
(This article belongs to the Special Issue Pigment Production in Submerged Fermentation)
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15 pages, 1849 KiB  
Review
Pentostatin Biosynthesis Pathway Elucidation and Its Application
by Hongyu Zhang, Ran Liu, Tingting Lou, Pei Zhao and Suying Wang
Fermentation 2022, 8(9), 459; https://doi.org/10.3390/fermentation8090459 - 14 Sep 2022
Cited by 2 | Viewed by 2300
Abstract
Pentostatin (PNT), a nucleoside antibiotic with a 1,3-diazo ring structure, is distributed in several actinomycetes and fungi species. Its special structure makes PNT possess a wide spectrum of biological and pharmacological properties, such as antibacterial, antitrypanosomal, anticancer, antiviral, herbicidal, insecticidal, and immunomodulatory effects. [...] Read more.
Pentostatin (PNT), a nucleoside antibiotic with a 1,3-diazo ring structure, is distributed in several actinomycetes and fungi species. Its special structure makes PNT possess a wide spectrum of biological and pharmacological properties, such as antibacterial, antitrypanosomal, anticancer, antiviral, herbicidal, insecticidal, and immunomodulatory effects. Because of the promising adenosine deaminase inhibitory activity of PNT, its extensive application in the clinical treatment of malignant tumors has been extensively studied. However, the fermentation level of microbial-derived PNT is low and cannot meet medical needs. Because the biosynthesis pathway of PNT is obscure, only high-yield mutant screening and optimization of medium components and fermentation processes have been conducted for enhancing its production. Recently, the biosynthesis pathways of PNT in actinomycetes and fungi hosts have been revealed successively, and the large-scale production of PNT by systematic metabolic engineering will become an inevitable trend. Therefore, this review covers all aspects of PNT research, in which major advances in understanding the resource microorganisms, mechanism of action, and biosynthesis pathway of PNT were achieved and diverse clinical applications of PNT were emphasized, and it will lay the foundation for commercial transformation and industrial technology of PNT based on systematic metabolic engineering. Full article
(This article belongs to the Special Issue Pharmaceutical Fermentation: Antibiotic Production and Processing)
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12 pages, 774 KiB  
Article
Evaluating the Influence of Microbial Fermentation on the Nutritional Value of Soybean Meal
by Stanislav Sukhikh, Olga Kalashnikova, Svetlana Ivanova, Alexander Prosekov, Olesia Krol, Olga Kriger, Nataly Fedovskikh and Olga Babich
Fermentation 2022, 8(9), 458; https://doi.org/10.3390/fermentation8090458 - 13 Sep 2022
Cited by 6 | Viewed by 2839
Abstract
The aim of this article is to increase the nutritional value of soybean meal while reducing the content of antinutrients by microbial fermentation of soybean meal with a mixed culture of probiotic microorganisms (Bacillus subtilis, Aspergillus niger, Saccharomyces cerevisiae, [...] Read more.
The aim of this article is to increase the nutritional value of soybean meal while reducing the content of antinutrients by microbial fermentation of soybean meal with a mixed culture of probiotic microorganisms (Bacillus subtilis, Aspergillus niger, Saccharomyces cerevisiae, Lactiplantibacillus plantarum) at two different hydromodules. The addition of microorganisms increased the content of easily digestible protein and amine nitrogen in fermented soybean meal (30:110 and 30:130, hydromodulus soybean meal:water) while decreasing urease activity (hydromodulus 30:110). The positive effect of microbial fermentation on the mineral composition of soybean meal was demonstrated. The ability of microorganisms in the fermentation process to increase the content of protein, essential amino acids, and macro- and microelements in soybean meal while decreasing anti-nutritional factors opens up possibilities for using this technology to advance animal husbandry. Full article
(This article belongs to the Special Issue Advances in Resource Recovery from Organic Wastes (ARROW))
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10 pages, 648 KiB  
Communication
Fermentative Production of Volatile Metabolites Using Brettanomyces bruxellensis from Fruit and Vegetable By-Products
by Melodie A. Lindsay, Ninna Granucci, David R. Greenwood and Silas G. Villas-Boas
Fermentation 2022, 8(9), 457; https://doi.org/10.3390/fermentation8090457 - 12 Sep 2022
Cited by 2 | Viewed by 1826
Abstract
Natural sources of flavour and aroma compounds are highly sought by the modern consumer; however, traditional sources are often low-yielding, and global supply is often outstripped by consumer demand. Fermentation is a favourable route by which natural flavours and fragrances can be produced. [...] Read more.
Natural sources of flavour and aroma compounds are highly sought by the modern consumer; however, traditional sources are often low-yielding, and global supply is often outstripped by consumer demand. Fermentation is a favourable route by which natural flavours and fragrances can be produced. A non-Saccharomyces yeast, Brettanomyces bruxellensis, was investigated for its fermentative potential for the production of flavour and aroma metabolites from juice industry by-products: apple pomace, carrot pomace, and orange pomace. Submerged solid-substrate fermentations were carried out using sterile by-products without nutrient supplementation. Gas chromatography–mass spectrometry was used for volatile metabolite profiling of fermented substrates. One compound of interest, phenylethyl alcohol (rose fragrance), was extracted and quantified using GC-MS at a yield of 2.68 g/kg wet carrot pomace weight. This represents a novel, natural production strategy for phenylethyl alcohol compared to the traditional steam distillation of Rosa domascus sp. petals. Full article
(This article belongs to the Special Issue Microbial Biotechnology and Agro-Industrial By-Products Fermentation)
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12 pages, 997 KiB  
Article
Non-Saccharomyces Are Also Forming the Veil of Flor in Sherry Wines
by Marina Ruiz-Muñoz, María Hernández-Fernández, Gustavo Cordero-Bueso, Sergio Martínez-Verdugo, Fernando Pérez and Jesús Manuel Cantoral
Fermentation 2022, 8(9), 456; https://doi.org/10.3390/fermentation8090456 - 12 Sep 2022
Cited by 5 | Viewed by 2194
Abstract
Biological ageing is an essential process for obtaining some distinctive Sherry wines, such as Fino and Manzanilla. It occurs after the fermentation of the grape must due to the appearance of a biofilm on the surface of the wine called “veil of flor”. [...] Read more.
Biological ageing is an essential process for obtaining some distinctive Sherry wines, such as Fino and Manzanilla. It occurs after the fermentation of the grape must due to the appearance of a biofilm on the surface of the wine called “veil of flor”. Yeasts belonging to the Saccharomyces cerevisiae species mainly comprise such biofilm. Although other species have also been found, these have been traditionally considered spoilage. Indeed, it has even been hypothesised that they may not be able to form biofilm on their own under such conditions. In the present work, four different non-Saccharomyces yeasts isolated from barrels in the Jerez area under biological ageing have been characterised through their physiological abilities, including extracellular enzymatic and biofilm-forming capabilities. Results showed not only a surprising ethanol tolerance, above 15.5% in all cases, but also a significant degree of extracellular enzyme production, highlighting the urease and proteolytic activities found in Pichia manshurica, as well as lipolytic activity in Pichia kudriavzevii, Pichia membranifaciens and Wicherhamomyces anomalus. As a conclusion, these non-Saccharomyces could be very interesting in the oenological field, beyond improving the organoleptic characteristics as well as technological features in these wines. Full article
(This article belongs to the Special Issue Enological Repercussions of Non-saccharomyces Species 4.0)
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13 pages, 1048 KiB  
Article
A Preliminary Study of Yeast Strain Influence on Chemical and Sensory Characteristics of Apple Cider
by Madeleine L. Way, Joanna E. Jones, Rocco Longo, Robert G. Dambergs and Nigel D. Swarts
Fermentation 2022, 8(9), 455; https://doi.org/10.3390/fermentation8090455 - 12 Sep 2022
Cited by 9 | Viewed by 2866
Abstract
During the fermentation of apple juice, yeast metabolism creates complex biosynthetic pathways which produce a range of compounds responsible for the organoleptic qualities of cider. In this study, basic cider quality parameters were measured to investigate the influence of six yeast strains on [...] Read more.
During the fermentation of apple juice, yeast metabolism creates complex biosynthetic pathways which produce a range of compounds responsible for the organoleptic qualities of cider. In this study, basic cider quality parameters were measured to investigate the influence of six yeast strains on cider made from three apple varieties (‘Pink Lady’, ‘Sturmer’, and ‘Bulmer’s Norman’). Measurement of pH, titratable acidity, and total phenolic content revealed that yeast can influence cider attributes, albeit variety and season dependent. Descriptive sensory analysis using a trained sensory panel was conducted on cider made from ‘Pink Lady’ apples and the same six yeast strains. The sensory panel significantly differentiated the yeast strains on the attributes of ‘fresh apple’, ‘earthy’ and ‘pear’. Identifying the variety specific influence of individual yeast strains on chemical and sensory characteristics of apple cider will provide cider makers with an enhanced understanding when choosing yeast strains. Full article
(This article belongs to the Special Issue Flavor and Aroma in the Fermented Food)
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18 pages, 2839 KiB  
Article
Effects of Lactobacillus curvatus HY7602-Fermented Antlers in Dexamethasone-Induced Muscle Atrophy
by Hyejin Jeon, Yong-Tae Kim, Woo Young Jang, Joo-Yun Kim, Keon Heo, Jae-Jung Shim, Jung-Lyoul Lee, Deok-Chun Yang and Se Chan Kang
Fermentation 2022, 8(9), 454; https://doi.org/10.3390/fermentation8090454 - 12 Sep 2022
Cited by 5 | Viewed by 2713
Abstract
This study assessed the improvements yielded by Lactobacillus curvatus HY7602-fermented antlers (FA) in dexamethasone-induced muscle atrophy and the effects of bioactive compounds increased by fermentation. Dexamethasone-treated C2C12 myoblast cells were treated with FA and non-fermented antlers (NFA). FA showed inhibitory effects on muscle [...] Read more.
This study assessed the improvements yielded by Lactobacillus curvatus HY7602-fermented antlers (FA) in dexamethasone-induced muscle atrophy and the effects of bioactive compounds increased by fermentation. Dexamethasone-treated C2C12 myoblast cells were treated with FA and non-fermented antlers (NFA). FA showed inhibitory effects on muscle protein degradation in the C2C12 cells. Hsb:ICR mice were orally administered saline (control(CON) and dexamethasone only (DEX)), oxymetholone (DEX+OXY), NFA (DEX+NFA), and FA (DEX+FA) via gavage. Before the end of the experiment, dexamethasone was intraperitoneally (IP) injected into the mice, except in the control group, to induce muscle atrophy. Compared with the DEX group, the DEX+FA group exhibited a significant prevention in the reduction of hindlimb strength, calf thickness, calf muscle weight, and the cross-sectional area of muscle fibers (p < 0.05). The FA-induced improvements in muscle atrophy were associated with a decreased gene expression of protein degradation and growth inhibition, and an increased gene expression of protein synthesis and growth factors. Sialic acid, a bioactive compound associated with muscles, was increased by 51.41% after fermentation and suppressed the expression of protein degradation genes in the C2C12 cells. L. curvatus HY7602-fermented antlers with increased sialic acid after fermentation may therefore be useful for preventing and improving muscle atrophy. Full article
(This article belongs to the Special Issue Bioactivity Change in Fermented Foods)
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18 pages, 3209 KiB  
Article
Integrating Torrefaction of Pulp Industry Sludge with Anaerobic Digestion to Produce Biomethane and Volatile Fatty Acids: An Example of Industrial Symbiosis for Circular Bioeconomy
by Tharaka Rama Krishna C. Doddapaneni, Margareta Novian Cahyanti, Kaja Orupõld and Timo Kikas
Fermentation 2022, 8(9), 453; https://doi.org/10.3390/fermentation8090453 - 11 Sep 2022
Cited by 4 | Viewed by 1964
Abstract
Industrial symbiosis, which allows the sharing of resources between different industries, could help to improve the overall feasibility of bio-based chemicals production. In that regard, this study focused on integrating the torrefaction of pulp industry sludge with anaerobic digestion. More specifically, anaerobic digestion [...] Read more.
Industrial symbiosis, which allows the sharing of resources between different industries, could help to improve the overall feasibility of bio-based chemicals production. In that regard, this study focused on integrating the torrefaction of pulp industry sludge with anaerobic digestion. More specifically, anaerobic digestion (AD) of pulp sludge-derived torrefaction condensate (TC) was studied to evaluate the biomethane and volatile fatty acid (VFA) potential. The torrefaction condensate produced at 275 and 300 °C was used in AD. The volatile solid content (VS) was 6.69 and 9.01% for the condensate produced at 275 and 300 °C, respectively. The organic fraction of TC mainly contained acetic acid, 2-furanmethanol, and syringol. The methane yield was in the range of 481–772 mL/g VS for the mesophilic and 401–746 mL/g VS for the thermophilic process, respectively. The VFA yield was in the range of 1.1 to 3.4 g/g VS for mesophilic and from 1.5 to 4.7 g/g VS in thermophilic conditions, when methanogenesis was inhibited. Finally, pulp sludge TC is a feasible feedstock to produce platform chemicals like VFA. However, at higher substrate loading, signs of process inhibition were observed because of the relatively increasing concentration of microbial inhibitors Full article
(This article belongs to the Special Issue Biological Conversion of Biomass Residues and Waste Streams for the Sustainable Production of Biofuels and Bio-Based Products)
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11 pages, 1802 KiB  
Article
Improved Tolerance of Lactiplantibacillus plantarum in the Presence of Acid by the Heterologous Expression of trxA from Oenococcus oeni
by Longxiang Liu, Xinyu Yu, Ming Wu, Keying Zhang, Shuai Shang, Shuai Peng and Weiyu Song
Fermentation 2022, 8(9), 452; https://doi.org/10.3390/fermentation8090452 - 11 Sep 2022
Cited by 1 | Viewed by 1575
Abstract
Oenococcus oeni is the main microorganism that undergoes malolactic fermentation (MLF) in the winemaking industry due to its excellent adaptability to harsh wine environments. The start of MLF is often delayed or even fails, and low pH appears to be a crucial parameter. [...] Read more.
Oenococcus oeni is the main microorganism that undergoes malolactic fermentation (MLF) in the winemaking industry due to its excellent adaptability to harsh wine environments. The start of MLF is often delayed or even fails, and low pH appears to be a crucial parameter. To study the function of the trxA gene in acid stress, a plasmid containing the trxA gene of O. oeni SD-2a was heterologously expressed in Lactiplantibacillus plantarum WCFS1. The recombinant strain (WCFS1-trxA) grew better than the control strain (WCFS1-Vector) under acid stress. The expression of thioredoxin system genes was much higher in the recombinant strain compared with the control strain under acid stress. In addition, a series of physiological and biochemical assays were conducted. The ATP content was lower in the recombinant strain, while the cell membrane fluidity and integrity improved in the recombinant strain. Moreover, reactive oxygen species (ROS) accumulation, intracellular GSH level, and superoxide dismutase (SOD) activity assays showed that the recombinant strain decreased the intracellular reactive oxygen species (ROS) accumulation by improving the SOD activity. In conclusion, heterologous expression of trxA improves the SOD activity of L. plantarum WCFS1, reducing bacterial ROS and increasing cell membrane fluidity and integrity, enhancing the tolerance of Lactiplantibacillus plantarum WCFS1 under acid stress. Full article
(This article belongs to the Topic Food Processing and Preservation)
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12 pages, 1184 KiB  
Article
Optimization of Growth Conditions to Enhance PHA Production by Cupriavidus necator
by Soňa Ronďošová, Barbora Legerská, Daniela Chmelová, Miroslav Ondrejovič and Stanislav Miertuš
Fermentation 2022, 8(9), 451; https://doi.org/10.3390/fermentation8090451 - 10 Sep 2022
Cited by 10 | Viewed by 3864
Abstract
The accumulation of polyhydroxyalkanoates (PHAs) by microorganisms usually occurs in response to environmental stress conditions. Therefore, it is advantageous to choose two-step cultivation. The first phase is aimed at maximizing biomass production, and only in the second phase, after setting the suitable conditions, [...] Read more.
The accumulation of polyhydroxyalkanoates (PHAs) by microorganisms usually occurs in response to environmental stress conditions. Therefore, it is advantageous to choose two-step cultivation. The first phase is aimed at maximizing biomass production, and only in the second phase, after setting the suitable conditions, PHA production starts. The aim of this work was to optimize the composition of the minimal propagation medium used for biomass production of Cupriavidus necator DSM 545 using the response surface methodology (RSM). Based on the results from the search for optimization limits, the glucose concentration, the ammonium sulfate concentration and the phosphate buffer molarity were chosen as independent variables. The optimal values were found as follows: the glucose concentration 10.8 g/L; the ammonium sulfate concentration 0.95 g/L; and the phosphate buffer molarity 60.2 mmol/L. The predicted biomass concentration was 4.54 g/L, and the verified value was at 4.84 g/L. Although this work was primarily focused on determining the optimal composition of the propagation medium, we also evaluated the optimal composition of the production medium and found that the optimal glucose concentration was 6.7 g/L; the ammonium sulfate concentration 0.60 g/L; and the phosphate buffer molarity 20 mmol/L. The predicted PHB yield was 54.7% (w/w) of dry biomass, and the verified value was 49.1%. Full article
(This article belongs to the Special Issue Fermentative Production of Biofuels and Bioproducts within a Biorefinery Perspective)
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13 pages, 982 KiB  
Article
Characterization of Non-Saccharomyces Yeast Strains Isolated from Grape Juice and Pomace: Production of Polysaccharides and Antioxidant Molecules after Growth and Autolysis
by Sabrina Voce, Lucilla Iacumin and Piergiorgio Comuzzo
Fermentation 2022, 8(9), 450; https://doi.org/10.3390/fermentation8090450 - 09 Sep 2022
Cited by 3 | Viewed by 1893
Abstract
Non-Saccharomyces yeasts (NSY) represent a relevant part of must and wine microbiota, contributing remarkably to the composition of lees biomass. Despite a number of studies indicate their capacity to increase wine polysaccharide content, their contribution to wine quality during aging on lees [...] Read more.
Non-Saccharomyces yeasts (NSY) represent a relevant part of must and wine microbiota, contributing remarkably to the composition of lees biomass. Despite a number of studies indicate their capacity to increase wine polysaccharide content, their contribution to wine quality during aging on lees (AOL) has not been well elucidated yet. In the present study, twenty yeast strains (13 non-Saccharomyces and 7 Saccharomyces) were isolated from grape must and pomace and identified by morphologic and genetic characterization. Biomass production, cell growth and the release of soluble molecules (polysaccharides, amino acids, thiol compounds and glutathione) were evaluated after growth and after autolysis induced by β-glucanases addition. Differences between strains were observed for all parameters. Strains that produced higher amounts of soluble compounds during growth also showed the highest release after autolysis. Hanseniaspora spp. showed the greatest production of polysaccharides and antioxidant molecules, and biomass production and cell viability comparable to the commercial S. cerevisiae and T. delbrueckii used as reference. The aptitude of certain NSY to release antioxidants and polysaccharides is an interesting feature for managing AOL through sequential or mixed fermentations or for the production of inactive autolyzed yeasts for winemaking. Full article
(This article belongs to the Special Issue Enological Repercussions of Non-saccharomyces Species 4.0)
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15 pages, 4645 KiB  
Article
Optimized Recombinant Expression and Characterization of Collagenase in Bacillus subtilis WB600
by Yaqing Zhu, Linlin Wang, Kaixuan Zheng, Ping Liu, Wenkang Li, Jian Lin, Wenjing Liu, Shoushui Shan, Liqin Sun and Hailing Zhang
Fermentation 2022, 8(9), 449; https://doi.org/10.3390/fermentation8090449 - 09 Sep 2022
Cited by 1 | Viewed by 2545
Abstract
Background: The collagenase encoding gene col was cloned into a pP43NMK vector and amplified in Escherichia coli JM109 cells. The shuttle vector pP43NMK was used to sub-clone the col gene to obtain the vector pP43NMK-col for the expression of collagenase in Bacillus [...] Read more.
Background: The collagenase encoding gene col was cloned into a pP43NMK vector and amplified in Escherichia coli JM109 cells. The shuttle vector pP43NMK was used to sub-clone the col gene to obtain the vector pP43NMK-col for the expression of collagenase in Bacillus subtilis WB600. The enzyme was characterized and the composition of the expression medium and culture conditions were optimized. Methods: The expressed recombinant enzyme was purified by ammonium sulfate, ultrafiltration, and through a nickel column. The purified collagenase had an activity of 9405.54 U/mg. Results: The recombinant enzyme exhibited optimal activity at pH 9.0 and 50 °C. Catalytic efficiency of the recombinant collagenase was inhibited by Fe3+ and Cu2+, but stimulated by Co2+, Ca2+, Zn2+, and Mg2+. The optimal conditions for its growth were at pH 7.0 and 35 °C, using 15 g/L of fructose and 36 g/L of yeast powder and peptone mixture (2:1) at 260 rpm with 11% inoculation. The maximal extracellular activity of the recombinant collagenase reached 2746.7 U/mL after optimization of culture conditions, which was 2.4-fold higher than that before optimization. Conclusions: This study is a first attempt to recombinantly express collagenase in B. subtilis WB600 and optimize its expression conditions, its production conditions, and possible scale-up. Full article
(This article belongs to the Special Issue Applied Microorganisms and Industrial/Food Enzymes)
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13 pages, 656 KiB  
Article
Single and Co-Cultures of Proteolytic Lactic Acid Bacteria in the Manufacture of Fermented Milk with High ACE Inhibitory and Antioxidant Activities
by Shahram Loghman, Ali Moayedi, Mandana Mahmoudi, Morteza Khomeiri, Laura G. Gómez-Mascaraque and Farhad Garavand
Fermentation 2022, 8(9), 448; https://doi.org/10.3390/fermentation8090448 - 09 Sep 2022
Cited by 7 | Viewed by 2027
Abstract
In this study, single and co-cultures of proteolytic Lactobacillus delberueckii subsp. bulgaricus ORT2, Limosilactobacillus reuteri SRM2 and Lactococcus lactis subsp. lactis BRM3 isolated from different raw milk samples were applied as starter cultures to manufacture functional fermented milks. Peptide extracts from fermented milk [...] Read more.
In this study, single and co-cultures of proteolytic Lactobacillus delberueckii subsp. bulgaricus ORT2, Limosilactobacillus reuteri SRM2 and Lactococcus lactis subsp. lactis BRM3 isolated from different raw milk samples were applied as starter cultures to manufacture functional fermented milks. Peptide extracts from fermented milk samples were evaluated after fermentation and 7 days of cold storage for proteolytic, angiotensin-converting enzyme (ACE) inhibitory and antioxidant activity by different methods including 2, 2′-diphenyl-1-picrylhydrazyl (DPPH), ferric-reducing antioxidant power (FRAP), OH-radical scavenging, and total antioxidant (molybdate-reducing activity). The highest proteolysis was found in milk fermented by co-cultures of three strains. Fermentation with the mentioned bacteria increased ACE inhibitory and antioxidant activity of the final products which were dependent on peptide concentration. The crude peptide extract obtained from fermented milk with triple co-culture showed the highest ACE inhibitory activity (IC50 = 0.61 mg/mL) which was reduced after 7 days of cold storage (IC50 = 0.78 mg/mL). Similar concentration-dependent activities were found in antioxidant activity at different antioxidant assays. Overall, high proteolytic activity resulted in increased ACE inhibitory and antioxidant activities, but the highest activity was not necessarily found for the samples with the highest proteolytic activity. The results of this study suggest the potential of using co-cultures of L. delberueckii subsp. bulgaricus, L. reuteri and L. lactis subsp. Lactis to manufacture antihypertensive fermented milk. Full article
(This article belongs to the Special Issue Postbiotics from Production to Their Health-Promoting Aspects)
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13 pages, 1447 KiB  
Article
The Biotransformation of Lupine Seeds by Lactic Acid Bacteria and Penicillium camemberti into a Plant-Based Camembert Alternative, and Its Physicochemical Changes during 7 Weeks of Ripening
by Łukasz Łopusiewcz, Natalia Śmietana, Elżbieta Lichwiarska, Kinga Mazurkiewicz-Zapałowicz, Annett Gefrom and Emilia Drozłowska
Fermentation 2022, 8(9), 447; https://doi.org/10.3390/fermentation8090447 - 08 Sep 2022
Cited by 1 | Viewed by 2431
Abstract
In recent years, there has been increasing consumer interest and research into plant-based dairy alternatives, due to the increasingly negative impact of animal products on human health, animal welfare, and the environment. The purpose of this study was to investigate the physicochemical and [...] Read more.
In recent years, there has been increasing consumer interest and research into plant-based dairy alternatives, due to the increasingly negative impact of animal products on human health, animal welfare, and the environment. The purpose of this study was to investigate the physicochemical and microbiological changes in a Camembert alternative based on the seeds of sweet lupine (Lupinus angustifolius L cv. ‘Boregine’). After heat treatment and homogenization, the seeds were incubated with lactic acid bacteria (LAB) and Penicillium camemberti mold. After fermentation at room temperature, the samples were stored at 12 °C for 14 days, and then ripened until day 49 at 6 °C. Changes in microbial population, acidity, texture, content of polyphenols, flavonoids, reducing sugars, and free amino acids were monitored. In addition, the antioxidant capacity of the samples during ripening was determined. The results showed that LAB and fungi were able to grow well in the lupine matrix. Initially, a decrease in pH was observed, while in the further stages of ripening, alkalization of the product linked with progressive proteolysis associated with an increase in free amino acid content was noted. Hydrolysis of polysaccharides and an increase in antioxidant activity were observed. This indicates the potential of lupine seeds as a raw material for the development of a new group of plant-based ripened cheese alternatives. Full article
(This article belongs to the Special Issue Biotransformation of Plant Materials by Molds and Higher Fungi)
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19 pages, 5851 KiB  
Article
Comparative Analysis of a Family of Sliding Mode Observers under Real-Time Conditions for the Monitoring in the Bioethanol Production
by Eduardo Alvarado-Santos, Juan L. Mata-Machuca, Pablo A. López-Pérez, Rubén A. Garrido-Moctezuma, Fermín Pérez-Guevara and Ricardo Aguilar-López
Fermentation 2022, 8(9), 446; https://doi.org/10.3390/fermentation8090446 - 07 Sep 2022
Cited by 5 | Viewed by 2123
Abstract
Online monitoring of fermentation processes is a necessary task to determine concentrations of key biochemical compounds, diagnose faults in process operations, and implement feedback controllers. However, obtaining the signals of all-important variables in a real process is a task that may be difficult [...] Read more.
Online monitoring of fermentation processes is a necessary task to determine concentrations of key biochemical compounds, diagnose faults in process operations, and implement feedback controllers. However, obtaining the signals of all-important variables in a real process is a task that may be difficult and expensive due to the lack of adequate sensors, or simply because some variables cannot be directly measured. From the above, a model-based approach such as state observers may be a viable alternative to solve the estimation problem. This work shows a comparative analysis of the real-time performance of a family of sliding-mode observers for reconstructing key variables in a batch bioreactor for fermentative ethanol production. These observers were selected for their robust performance under model uncertainties and finite-time estimation convergence. The selected sliding-mode observers were the first-order sliding mode observer, the proportional sliding mode observer, and the high-order sliding mode observer. For estimation purposes, a power law kinetic model for ethanol production by Saccharomyces cerevisiae was performed. A hybrid methodology allows the kinetic parameters to be adjusted, and an approach based on inference diagrams allows the observability of the model to be determined. The experimental results reported here show that the observers under analysis were robust to modeling errors and measurement noise. Moreover, the proportional sliding-mode observer was the algorithm that exhibited the best performance. Full article
(This article belongs to the Topic Bioreactors: Control, Optimization and Applications)
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25 pages, 1119 KiB  
Review
Current Trends in Biological Valorization of Waste-Derived Biomass: The Critical Role of VFAs to Fuel A Biorefinery
by Corine Nzeteu, Fabiana Coelho, Emily Davis, Anna Trego and Vincent O’Flaherty
Fermentation 2022, 8(9), 445; https://doi.org/10.3390/fermentation8090445 - 07 Sep 2022
Cited by 7 | Viewed by 4719
Abstract
The looming climate and energy crises, exacerbated by increased waste generation, are driving research and development of sustainable resource management systems. Research suggests that organic materials, such as food waste, grass, and manure, have potential for biotransformation into a range of products, including: [...] Read more.
The looming climate and energy crises, exacerbated by increased waste generation, are driving research and development of sustainable resource management systems. Research suggests that organic materials, such as food waste, grass, and manure, have potential for biotransformation into a range of products, including: high-value volatile fatty acids (VFAs); various carboxylic acids; bioenergy; and bioplastics. Valorizing these organic residues would additionally reduce the increasing burden on waste management systems. Here, we review the valorization potential of various sustainably sourced feedstocks, particularly food wastes and agricultural and animal residues. Such feedstocks are often micro-organism-rich and well-suited to mixed culture fermentations. Additionally, we touch on the technologies, mainly biological systems including anaerobic digestion, that are being developed for this purpose. In particular, we provide a synthesis of VFA recovery techniques, which remain a significant technological barrier. Furthermore, we highlight a range of challenges and opportunities which will continue to drive research and discovery within the field. Analysis of the literature reveals growing interest in the development of a circular bioeconomy, built upon a biorefinery framework, which utilizes biogenic VFAs for chemical, material, and energy applications. Full article
(This article belongs to the Special Issue Anaerobic Fermentation – a Biological Route towards Achieving Net Neutrality)
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14 pages, 2649 KiB  
Article
A Novel Salt-Tolerant L-Glutaminase: Efficient Functional Expression, Computer-Aided Design, and Application
by Hengwei Zhang, Mengkai Hu, Qing Wang, Fei Liu, Meijuan Xu, Xian Zhang and Zhiming Rao
Fermentation 2022, 8(9), 444; https://doi.org/10.3390/fermentation8090444 - 06 Sep 2022
Cited by 6 | Viewed by 1828
Abstract
The low productivity in long fermentation duration and high-salt working conditions limit the application of L-glutaminase in soy sauce brewing. In this study, a novel L-glutaminase (LreuglsA) with eminent salt tolerance was mined and achieved more than 70% activity with 30% NaCl. To [...] Read more.
The low productivity in long fermentation duration and high-salt working conditions limit the application of L-glutaminase in soy sauce brewing. In this study, a novel L-glutaminase (LreuglsA) with eminent salt tolerance was mined and achieved more than 70% activity with 30% NaCl. To improve the robustness of the enzyme at different fermentation strategies, mutation LreuglsAH105K was built by a computer-aided design, and the recombinant protein expression level, an essential parameter in industrial applications, was increased 5.61-fold with the synthetic biology strategy by improving the mRNA stability. Finally, the LreuglsAH105K functional expression box was contributed to Bacillus subtilis 168 by auxotrophic complementation, and the production in a 5-L bioreactor was improved to 2516.78 ± 20.83 U mL−1, the highest production ever reported. When the immobilized cells were applied to high-salt dilute-state soy sauce brewing, the L-glutamate level was increased by 45.9%. This work provides insight into the salt-tolerant enzyme for improving the efficiency of industrial applications. Full article
(This article belongs to the Special Issue Applied Microorganisms and Industrial/Food Enzymes)
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16 pages, 894 KiB  
Article
The Effect of Forage Source and Concentrated Liquid Feedstuff Supplementation on Improving the Synchronization of Ruminant Dietary Energy and Nitrogen Release In Vitro
by Yi-Hsuan Chen, Ching-Yi Chen and Han-Tsung Wang
Fermentation 2022, 8(9), 443; https://doi.org/10.3390/fermentation8090443 - 06 Sep 2022
Cited by 1 | Viewed by 1473
Abstract
This study aimed to investigate the effect of supplementation with a mixture of molasses and condensed molasses fermentation solubles (M-CMS) in different synchronization diets formulated with different forage sources in an attempt to improve the fermentation efficiency of diets by M-CMS. In the [...] Read more.
This study aimed to investigate the effect of supplementation with a mixture of molasses and condensed molasses fermentation solubles (M-CMS) in different synchronization diets formulated with different forage sources in an attempt to improve the fermentation efficiency of diets by M-CMS. In the first experiment, three levels of M-CMS (N: 0%; L: 1.75%; and H: 3.50%) were supplied to diets with or without corn silage to evaluate the supplementation effect on the diet with a synchrony index (SI) of 0.80. In the second experiment, diets containing different corn silage levels (60 or 30% of the forage source) were used to evaluate the effects of M-CMS supplementation on higher SI (at 0.88). The in vitro digestibility, fermentation products, microbial crude protein (MCP), and gas kinetic parameters were determined after 48 h of fermentation. The results demonstrated that M-CMS supplementation improved MCP synthesis in both diets with low and high SI, but did not enhance digestibility. M-CMS supplementation was beneficial to the fermentation stability and extent. It also affected the gas kinetic parameters of the fast- and slow-degradation fractions during fermentation. M-CMS supplementation improved MCP synthesis in diets containing less corn silage. The forage source and degradation rate of individual ingredients should be considered simultaneously to enhance the rumen fermentation efficiency. M-CMS provided a practical choice to further improve MCP synthesis and fermentation stability, even in a diet with high SI. Full article
(This article belongs to the Section Industrial Fermentation)
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4 pages, 200 KiB  
Editorial
New Insights into the Application of Lactic Acid Bacterial Strains in Fermentation
by Ming-Kuei Shih, Bao-Hong Lee and Chih-Yao Hou
Fermentation 2022, 8(9), 442; https://doi.org/10.3390/fermentation8090442 - 06 Sep 2022
Viewed by 1479
Abstract
In recent years, lactic acid bacteria, widely used in food fermentation, have been recognized as beneficial components of the human microbiome in which they play an important role [...] Full article
(This article belongs to the Special Issue New Insights into the Application of Lactic Acid Bacteria Strain in the Fermentation)
17 pages, 3662 KiB  
Article
Influence of 1-Methylcyclopropene (1-MCP) on the Processing and Microbial Communities of Spanish-Style and Directly Brined Green Table Olive Fermentations
by Elio López-García, Antonio Benítez-Cabello, Francisco Rodríguez-Gómez, Virginia Martín-Arranz, Antonio Garrido-Fernández and Francisco Noé Arroyo-López
Fermentation 2022, 8(9), 441; https://doi.org/10.3390/fermentation8090441 - 05 Sep 2022
Cited by 2 | Viewed by 1567
Abstract
This work evaluates the effect of 1-methylcyclopropene (1-MCP) on postharvest and fermentation of Manzanilla cultivar, processed as Spanish-style or directly brined table olives. During postharvest handling, 1-MCP (2.85 µL/L) reduced the number of colour-turning olives by 18.42% over the untreated fruits. In Spanish-style [...] Read more.
This work evaluates the effect of 1-methylcyclopropene (1-MCP) on postharvest and fermentation of Manzanilla cultivar, processed as Spanish-style or directly brined table olives. During postharvest handling, 1-MCP (2.85 µL/L) reduced the number of colour-turning olives by 18.42% over the untreated fruits. In Spanish-style and directly brined fermentation, the 1-MCP treatment led to lower pH levels, higher titratable acidities, improved firmness and colour olives than untreated fruits. A panel of expert testers also gave higher scores, and overall acceptability to the 1-MCP treated fruits, especially in the case of Spanish-style fermented olives. Metagenomic analysis of olive biofilms at the end of the fermentation process (176 days) revealed that Lactiplantibacillus was the most abundant bacterial genus in both Spanish-style and directly brined olives (>72%). However, fungal biodiversity was higher than bacterial in all treatments. Saccharomyces was the predominant yeast genus associated with directly brined olives (>97%), whilst Wickerhamomyces (>37%) and Zygoascus (>18%) were with Spanish-style fermentations. The 1-MCP treatment doubled the presence of Wickerhamomyces in Spanish-style fruits (74%) whilst reducing the presence of Zygoascus and allowing the growth of Enterobacter (15%) in directly brined olives. Thus, the postharvesting treatment of table olives with 1-MCP could help reduce the maturation progress of olives and improve the organoleptic and quality characteristics of the products without affecting the microbiological evolution of the fermentations. Full article
(This article belongs to the Special Issue Evolution of Microbial Communities during Food Fermentation)
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11 pages, 1588 KiB  
Article
Pigment Production by Paracoccus spp. Strains through Submerged Fermentation of Valorized Lignocellulosic Wastes
by Weronika Pyter, Jasneet Grewal, Dariusz Bartosik, Lukasz Drewniak and Kumar Pranaw
Fermentation 2022, 8(9), 440; https://doi.org/10.3390/fermentation8090440 - 05 Sep 2022
Cited by 6 | Viewed by 2287
Abstract
Due to the increasing emphasis on the circular economy, research in recent years has focused on the feasibility of using biomass as an alternative energy source. Plant biomass is a potential substitute for countering the dependence on depleting fossil-derived energy sources and chemicals. [...] Read more.
Due to the increasing emphasis on the circular economy, research in recent years has focused on the feasibility of using biomass as an alternative energy source. Plant biomass is a potential substitute for countering the dependence on depleting fossil-derived energy sources and chemicals. However, in particular, lignocellulosic waste materials are complex and recalcitrant structures that require effective pretreatment and enzymatic saccharification to release the desired saccharides, which can be further fermented into a plethora of value-added products. In this context, pigment production from waste hydrolysates is a viable ecological approach to producing safe and natural colorings, which are otherwise produced via chemical synthesis and raise health concerns. The present study aims to evaluate two such abundant lignocellulosic wastes, i.e., wheat straw and pinewood sawdust as low-cost feedstocks for carotenoid production with Paracoccus strains. An alkali pretreatment approach, followed by enzymatic saccharification using an indigenous lab-isolated fungal hydrolase, was found to be effective for the release of fermentable sugars from both substrates. The fermentation of the pretreated sawdust hydrolysate by Paracoccus aminophilus CRT1 and Paracoccus kondratievae CRT2 resulted in the highest carotenoid production, 631.33 and 758.82 μg/g dry mass, respectively. Thus, the preliminary but informative research findings of the present work exhibit the potential for sustainable and economically feasible pigment production from lignocellulosic feedstocks after optimal process development on the pilot scale. Full article
(This article belongs to the Special Issue Pigment Production in Submerged Fermentation)
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