Fermentation

17 pages, 1155 KiB

Open AccessArticle

Sourdough Fermentation of Oat and Barley Flour with Bran and Its Application in Flatbread Made with No-Time and Dough Retardation Methods

by Tomislava Grgić, Saša Drakula, Bojana Voučko, Nikolina Čukelj Mustač and Dubravka Novotni

Fermentation 2024, 10(3), 174; https://doi.org/10.3390/fermentation10030174 - 21 Mar 2024

Viewed by 869

Abstract

Dough retardation is commonly used to extend dough shelf-life, but it poses a challenge for flatbreads due to their large surface. This study explored the sourdough fermentation of oats and barley, addressing challenges in the retardation of dough for flatbread. Sourdough, using flour [...] Read more.

Dough retardation is commonly used to extend dough shelf-life, but it poses a challenge for flatbreads due to their large surface. This study explored the sourdough fermentation of oats and barley, addressing challenges in the retardation of dough for flatbread. Sourdough, using flour only or flour blended with bran (3:1), was fermented with a LIVENDO LV1 starter at 30 °C for 24 h. The pH value, microbial viable cell count, total titratable acidity and organic acids concentration of the sourdough were measured. The properties of dough and flatbread, depending on the retardation time (24 h and 48 h), sourdough type (oat or barley) and sourdough level (30% or 50% dough weight), were investigated. Oat flour’s limited acidification improved with the inclusion of bran, resulting in a desirable pH, TTA, and lactic to acetic acid ratio after 15 h of fermentation, which were comparable to results achieved with barley sourdough. The sourdough addition slowed down the enzymatic browning of dough during retardation. Dough retardation at 24 h reduced the phytates content (32–38%) and crumb hardness (9–16%), depending on the sourdough type and level. In dough retardation, β-glucans were degraded by up to 9% in the case of oats and by up to 28% in the samples with barley. Overall, adding oat or barley sourdough at a 30% dough weight can be recommended to enhance flatbread’s nutritional value and prolong its shelf life. Full article

(This article belongs to the Special Issue Nutrition and Health of Fermented Foods, 3rd Edition)

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11 pages, 1545 KiB

Open AccessArticle

The Biosynthesis of the Monoterpene Tricyclene in E. coli through the Appropriate Truncation of Plant Transit Peptides

by Meijia Zhao, Shaoheng Bao, Jiajia Liu, Fuli Wang, Ge Yao, Penggang Han, Xiukun Wan, Chang Chen, Hui Jiang, Xinghua Zhang and Wenchao Zhu

Fermentation 2024, 10(3), 173; https://doi.org/10.3390/fermentation10030173 - 20 Mar 2024

Viewed by 841

Abstract

Tricyclene, a tricyclic monoterpene naturally occurring in plant essential oils, holds potential for the development of medicinal and fuel applications. In this study, we successfully synthesized tricyclene in E. coli by introducing the heterologous mevalonate (MVA) pathway along with Abies grandis geranyl diphosphate [...] Read more.

Tricyclene, a tricyclic monoterpene naturally occurring in plant essential oils, holds potential for the development of medicinal and fuel applications. In this study, we successfully synthesized tricyclene in E. coli by introducing the heterologous mevalonate (MVA) pathway along with Abies grandis geranyl diphosphate synthase (GPPS) and Nicotiana sylvestris tricyclene synthase (TS) XP_009791411. Initially, the shake-flask fermentation at 30 ^◦C yielded a tricyclene titer of 0.060 mg/L. By increasing the copy number of the TS-coding gene, we achieved a titer of 0.103 mg/L. To further enhance tricyclene production, optimal truncation in the N-terminal region of TS XP_009791411 resulted in an impressive highest titer of 47.671 mg/L, approximately a 794.5-fold improvement compared to its wild-type counterpart. To the best of our knowledge, this is the highest titer of the heterologous synthesis of tricyclene in E. coli. The SDS-PAGE analysis revealed that lowering induction temperature and truncating the random coil N-terminal region effectively improved TS solubility, which was closely associated with tricyclene production levels. Furthermore, by truncating other TSs, the titers of tricyclene were improved to different degrees. Full article

(This article belongs to the Special Issue Fermentation: 10th Anniversary)

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5 pages, 199 KiB

Open AccessEditorial

Yeast Biotechnology 6.0

by Ronnie G. Willaert

Fermentation 2024, 10(3), 172; https://doi.org/10.3390/fermentation10030172 - 19 Mar 2024

Viewed by 772

Abstract

This Special Issue continues the “Yeast Biotechnology” Special Issue series of the MDPI journal Fermentation [...] Full article

(This article belongs to the Special Issue Yeast Biotechnology 6.0)

12 pages, 220 KiB

Open AccessCorrection

Correction: Bintsis, T.; Papademas, P. The Evolution of Fermented Milks, from Artisanal to Industrial Products: A Critical Review. Fermentation 2022, 8, 679

by Thomas Bintsis and Photis Papademas

Fermentation 2024, 10(3), 171; https://doi.org/10.3390/fermentation10030171 - 19 Mar 2024

Viewed by 549

Abstract

In the original publication [...] Full article

(This article belongs to the Section Fermentation for Food and Beverages)

12 pages, 1338 KiB

Open AccessArticle

Effect of High Altitude on Serum Biochemical Parameters, Immunoglobulins, and Rumen Metabolism of Sanhe Heifers

by Xinyu Zhang, Zhijun Cao, Hongjian Yang, Yajing Wang, Wei Wang and Shengli Li

Fermentation 2024, 10(3), 170; https://doi.org/10.3390/fermentation10030170 - 18 Mar 2024

Viewed by 765

Abstract

Rumen metabolism is closely related to feed utilization and the environmental adaptability of cows. However, information on the influence of altitude on ruminal metabolism is limited. Our study aimed to investigate differences in rumen metabolism and blood biochemical indicators among Sanhe heifers residing [...] Read more.

Rumen metabolism is closely related to feed utilization and the environmental adaptability of cows. However, information on the influence of altitude on ruminal metabolism is limited. Our study aimed to investigate differences in rumen metabolism and blood biochemical indicators among Sanhe heifers residing at various altitudes. A total of 20 serum and ruminal fluid samples were collected from Sanhe heifers in China, including those from Hulunbeier City (approximately 700 m altitude; 119°57′ E, 47°17′ N; named LA) and Lhasa City (approximately 3650 m altitude; 91°06′ E, 29°36′ N; named HA). Compared with LA heifers, HA heifers had higher levels of serum cortisol, glucose, and blood urea nitrogen (p < 0.05) and lower Ca²⁺ concentrations (p < 0.05). Using liquid chromatography–mass spectrometry (LC–MS)-based untargeted metabolomic technology, we identified a significant difference in 312 metabolites between the LA and HA groups. Metabolic pathway analysis, based on significantly different rumen metabolites, identified 20 enriched metabolic pathways within hierarchy III, which are encompassed within 6 broader metabolic pathways in hierarchy I. This study constitutes the first elucidation of the altitudinal adaptation mechanism of ruminants from the perspective of rumen metabolism, thereby offering a novel angle for investigating high-altitude adaptation in both humans and animals. Full article

(This article belongs to the Section Microbial Metabolism, Physiology & Genetics)

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13 pages, 918 KiB

Open AccessReview

Sanitizers Used for Fungal Spoilage Control in Dry-Fermented Cured Meat Production

by Sarah Silva, Angélica Olivier Bernardi, Marcelo Valle Garcia, Thais Nunes Bisello, Larissa Borstmann and Marina Venturini Copetti

Fermentation 2024, 10(3), 169; https://doi.org/10.3390/fermentation10030169 - 15 Mar 2024

Viewed by 829

Abstract

Contamination caused by fungi stands out as a significant microbiological issue in the food industry, particularly leading to premature spoilage across various food segments, including the dry-fermented meat industry. The emergence of undesired fungi on product surfaces results in substantial economic losses. Once [...] Read more.

Contamination caused by fungi stands out as a significant microbiological issue in the food industry, particularly leading to premature spoilage across various food segments, including the dry-fermented meat industry. The emergence of undesired fungi on product surfaces results in substantial economic losses. Once microorganisms infiltrate the food, contamination ensues, and their subsequent proliferation can adversely impact the product’s appearance, odor, flavor, and texture. This, in turn, leads to consumer rejection and negatively affects the commercial brand. Additionally, concerns persist regarding the potential presence of mycotoxins in these products. Given the detrimental effects of spoilage fungi in the food industry, practices such as thorough cleaning and sanitization become crucial to prevent contamination and subsequent premature deterioration. These measures play a pivotal role in ensuring the quality and safety of food, while also extending the shelf life of products. This review delves into the advantages, disadvantages, and factors that may influence the efficacy of commonly used sanitizers in the dry-fermented cured meat industry, including substances like sodium hypochlorite, peracetic acid, and benzalkonium chloride. Full article

(This article belongs to the Special Issue Feature Review Papers in Fermentation for Food and Beverages 2023)

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18 pages, 1878 KiB

Open AccessReview

Lactic Acid Fermentation in the Food Industry and Bio-Preservation of Food

by Yulma Lizbeth Aguirre-Garcia, Sendar Daniel Nery-Flores, Lizeth Guadalupe Campos-Muzquiz, Adriana Carolina Flores-Gallegos, Lissethe Palomo-Ligas, Juan Alberto Ascacio-Valdés, Leonardo Sepúlveda-Torres and Raúl Rodríguez-Herrera

Fermentation 2024, 10(3), 168; https://doi.org/10.3390/fermentation10030168 - 15 Mar 2024

Viewed by 1133

Abstract

Studies on fermentation by acid lactic bacteria (LAB) have confirmed the presence of strains with attributes of considerable relevance for food processing. These strains, in addition to their ability to modify the texture and flavor of foods, possess beneficial properties for human health. [...] Read more.

Studies on fermentation by acid lactic bacteria (LAB) have confirmed the presence of strains with attributes of considerable relevance for food processing. These strains, in addition to their ability to modify the texture and flavor of foods, possess beneficial properties for human health. They enhance food quality by making it more nutrient-rich and contribute to food preservation. The production of lactic acid, vitamins, exopolysaccharides, and bacteriocins, among other compounds, confers these properties to LAB. In the realm of preservation, bacteriocins play a crucial role. This is because bacteriocins act by inhibiting the growth and reproduction of unwanted microorganisms by interacting with the cell membrane, causing its rupture. This preservative effect has led LAB to have widespread use during food processing. This preservative effect has led to widespread use of LAB during food processing. This review highlights the importance of fermentation carried out by LAB in the food industry and in the bio-preservation of foods. These findings emphasize the relevance of continuing investigations and harness the properties of LAB in food production. Full article

(This article belongs to the Special Issue Fermentation: 10th Anniversary)

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14 pages, 2278 KiB

Open AccessReview

Research Progress in Understanding the Molecular Biology of Cordyceps militaris

by Lihong Wang, Ganghua Li, Xueqin Tian, Yitong Shang, Huanhuan Yan, Lihua Yao and Zhihong Hu

Fermentation 2024, 10(3), 167; https://doi.org/10.3390/fermentation10030167 - 15 Mar 2024

Viewed by 1172

Abstract

Cordyceps militaris (C. militaris) is a valued medicinal fungus that can be traced back thousands of years in traditional Chinese medicine (TCM). Both TCM and modern scientific research have confirmed the positive effects of C. militaris on human health. In recent [...] Read more.

Cordyceps militaris (C. militaris) is a valued medicinal fungus that can be traced back thousands of years in traditional Chinese medicine (TCM). Both TCM and modern scientific research have confirmed the positive effects of C. militaris on human health. In recent years, C. militaris has gained wide popularity; unfortunately, strains often degrade during cultivation, resulting in a decline in fruiting bodies and active components that negatively impacts the development of C. militaris in the health food and medicine industries. This review summarizes the current progresses in research on the genomic, transcriptomic, proteomic, and genetic manipulation of C. militaris and discusses its primary metabolites and strain degradation mechanisms. The current challenges and future prospects of C. militaris research are also discussed. Full article

(This article belongs to the Special Issue Production of Nutritional and Functional Properties in Genetically Engineered Microorganisms)

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13 pages, 2567 KiB

Open AccessArticle

Distinct Short-Term Response of Intracellular Amino Acids in Saccharomyces cerevisiae and Pichia pastoris to Oxidative and Reductive Stress

by Burcu Şirin Kaya and Emrah Nikerel

Fermentation 2024, 10(3), 166; https://doi.org/10.3390/fermentation10030166 - 15 Mar 2024

Viewed by 872

Abstract

Despite being frequently encountered, the effect of oxidative or reductive stress on the intracellular metabolism and the response of the intracellular metabolome of yeasts is severely understudied. Non-conventional yeasts are attracting increasing attention due to their large substrate portfolio of non-canonical pathways as [...] Read more.

Despite being frequently encountered, the effect of oxidative or reductive stress on the intracellular metabolism and the response of the intracellular metabolome of yeasts is severely understudied. Non-conventional yeasts are attracting increasing attention due to their large substrate portfolio of non-canonical pathways as well as their production and secretion of proteins. To understand the effects of both stresses on yeast, the conventional model yeast S. cerevisiae and the non-conventional model yeast P. pastoris were perturbed with 5 mM of hydrogen peroxide for oxidative stress and 20 mM of dithiothreitol for reductive stress in well-defined chemostat cultures at a steady state, and fermentation profiles, intracellular amino acid levels, and intracellular glutathione levels were measured. Although stable profiles of extracellular metabolites were observed, significant changes were measured in intracellular amino acid levels within the first five minutes. Collectively, the amino acids ranged from 0.5 to 400 µmol/gDW, with the most significant increase upon the induction of oxidative stress being seen in cysteine (up to 90%) for S. cerevisiae and in aspartate (up to 80%) for P. pastoris. Upon the induction of reductive stress, asparagine nearly halves in S. cerevisiae, while tryptophan decreases by 60% in P. pastoris. By inspecting the time traces of each amino acid, possible mechanisms of pathway kinetics are speculated. This work furthers our understanding of the response of metabolism to oxidative stress in two model yeasts. Full article

(This article belongs to the Section Microbial Metabolism, Physiology & Genetics)

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23 pages, 4888 KiB

Open AccessArticle

Source-Separated Industrial Wastewater Is a Candidate for Biogas Production through Anaerobic Digestion

by Jake A. K. Elliott, Christian Krohn and Andrew S. Ball

Fermentation 2024, 10(3), 165; https://doi.org/10.3390/fermentation10030165 - 14 Mar 2024

Viewed by 792

Abstract

Anaerobic digestion is a potential treatment for industrial wastewater that provides valuable end-products, including renewable energy (biogas). However, waste streams may be too variable, too dilute at high volumes, or missing key components for stable digestion; all factors that increase costs and operational [...] Read more.

Anaerobic digestion is a potential treatment for industrial wastewater that provides valuable end-products, including renewable energy (biogas). However, waste streams may be too variable, too dilute at high volumes, or missing key components for stable digestion; all factors that increase costs and operational difficulty, making optimisation crucial. Anaerobic digestion may benefit from process intensification, particularly the novel combination of high-strength source-separated wastewater to minimise volume, together with the use of biosolids biochar as a chemical and microbial stabiliser. This study investigates the stability, yield, and microbial community dynamics of the anaerobic digestion of source-separated industrial wastewater from a food manufacturer and a logistics company, using biosolids biochar as an additive, focusing on gas and volatile fatty acid (VFA) production, process stability, and the microbial community using bench-scale semi-continuous reactors at 30- and 45-day hydraulic retention time (HRT). While gas yields were lower than expected, stability was possible at high HRT. Methane production reached 0.24 and 0.43 L day⁻¹ per litre reactor working volume at 30- and 45-day HRT, respectively, despite high VFA concentration, and was linked to the relative abundance of Methanosarcina in the microbial community. Interactions between substrate, VFA concentration, and the microbial community were observed. Biochar-assisted anaerobic digestion holds promise for the treatment of source-separated wastewater. Full article

(This article belongs to the Special Issue Energy Recovery Potential from Wastewater through Anaerobic Treatment)

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16 pages, 1228 KiB

Open AccessArticle

The Application of the Ultrasound Technique in the Production of Rosé and Red Wines

by Victoria Lizama, Inmaculada Álvarez and María José García-Esparza

Fermentation 2024, 10(3), 164; https://doi.org/10.3390/fermentation10030164 - 14 Mar 2024

Viewed by 710

Abstract

The application of the ultrasound technique (US) in the production of rosé and red wines has demonstrated that the aromatic composition of rose wine can be affected and that it contributes to increasing the color of red wines without increasing the extraction of [...] Read more.

The application of the ultrasound technique (US) in the production of rosé and red wines has demonstrated that the aromatic composition of rose wine can be affected and that it contributes to increasing the color of red wines without increasing the extraction of astringent tannins. The ultrasound treatment has favored the extraction of anthocyanins, which has had an impact on the increase in color density (C.D.) and has allowed greater color stability over time. Moreover, significant differences have been found between the two US systems applied, with continuous treatment being more effective in the extraction of phenolic compounds than pulsed treatment. The application system of the US also affects the aromatic composition of the wines. These results are of interest, as some esters have been described as important odorants in wines. Full article

(This article belongs to the Special Issue Fermented Beverages Revisited: From Terroir to Customized Functional Products, 2nd Edition)

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21 pages, 1443 KiB

Open AccessArticle

Life Cycle Assessment of Exopolysaccharides and Phycocyanin Production with Arthrospira platensis

by Isadora Cogo Badan, Sun-Hwa Jung, Rickwinder Singh, Vivekanand Vivekanand, Justus Knappert, Cornelia Rauh and Christoph Lindenberger

Fermentation 2024, 10(3), 163; https://doi.org/10.3390/fermentation10030163 - 13 Mar 2024

Viewed by 1351

Abstract

In the pursuit of sustainable solutions for contemporary environmental challenges arising from the increasing global demand for energy, this study delves into the potential of cyanobacteria, specifically Arthrospira platensis (commonly known as “spirulina”), as a versatile resource. Employing a life cycle assessment (LCA) [...] Read more.

In the pursuit of sustainable solutions for contemporary environmental challenges arising from the increasing global demand for energy, this study delves into the potential of cyanobacteria, specifically Arthrospira platensis (commonly known as “spirulina”), as a versatile resource. Employing a life cycle assessment (LCA) in accordance with the ISO 14044:2006 standard and employing both midpoint and endpoint indicators, the study comprehensively evaluates environmental impacts. The research explored a range of scenarios, specifically investigating variations in light intensity and harvesting volume. These investigations were carried out using a pilot-scale photobioreactor, specifically an airlift reactor system featuring a horizontal tubular downcomer. The primary focus is on extracting valuable compounds, namely exopolysaccharides and phycocyanin. It emphasized the extraction of value-added products and strategic integration with a biogas plant for process heat, contributing to developing a sustainable supply network and offering insights into environmentally conscious algae cultivation practices with implications for renewable energy and the production of valuable products. The results emphasize the project’s potential economic feasibility with minimal energy impact from by-product extraction. The environmental assessment identifies marine ecotoxicity and fossil resource depletion as principal impacts, predominantly influenced by upstreaming and harvesting stages. After conducting comparisons across various scenarios, it was found that cultivations under higher light intensities have a lower environmental impact than cultivations with low light supply. However, regardless of light intensity, processes with shorter harvesting cycles tend to have a smaller environmental impact compared to processes with longer harvesting cycles. Overall, this research contributes a nuanced and realistic perspective, fostering informed decision-making in sustainable algae cultivation practices, with implications for renewable energy and valuable compound production. Full article

(This article belongs to the Special Issue Cyanobacteria and Eukaryotic Microalgae)

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18 pages, 2048 KiB

Open AccessArticle

Acidogenic Fermentation of Food Waste for the Production of Short-Chain Fatty Acids: The Impact of Inoculum Type and Inoculum Heat Pretreatment

by Sharli Jodhani, Joseph Sebastian, Jangho Lee, Kaushik Venkiteshwaran, Hyung-Sool Lee, Virender Singh, Banu Ormeci and Abid Hussain

Fermentation 2024, 10(3), 162; https://doi.org/10.3390/fermentation10030162 - 12 Mar 2024

Viewed by 1040

Abstract

Acidogenic fermentation is an emerging biotechnology that allows for the utilization of food waste as a feedstock to produce high-value products such as short-chain fatty acids (SCFAs), effectively offering a tangible solution for food waste management as well as resource recovery. The objectives [...] Read more.

Acidogenic fermentation is an emerging biotechnology that allows for the utilization of food waste as a feedstock to produce high-value products such as short-chain fatty acids (SCFAs), effectively offering a tangible solution for food waste management as well as resource recovery. The objectives of the current study were to identify the ideal inoculum, waste-activated sludge (WAS) or anaerobic digester sludge (AD), for the acidogenic fermentation of food waste at room temperature, as well as to evaluate the impact of heat pretreatment of these inoculums on fermentation performance. The maximum hydrolysis yield of 399 g sCOD/kg VS _added was obtained when untreated AD was used as the inoculum, whereas the pretreated AD inoculum provided the highest SCFA yield and conversion efficiency of 238 g sCOD_SCFA/kg VS _added and 71%, respectively. Heat pretreatment had a detrimental impact on the WAS inoculum, leading to lower hydrolysis and SCFA yields, but exerted a positive influence on the AD inoculum. The microbial community showed that heat pretreatment negatively impacted the abundance of non-spore-forming hydrolytic and acidogenic microorganisms. Overall, this study demonstrates the critical role of inoculum type and heat pretreatment in optimizing the acidogenic fermentation process, laying the groundwork for future refinements in SCFA production from food waste through inoculum design. Full article

(This article belongs to the Special Issue Biotechnological Approaches for Food Waste Valorization)

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13 pages, 801 KiB

Open AccessArticle

Simultaneous Saccharification and Fermentation for Isobutanol Production from Banana Peel

by Hironaga Akita, Shodai Shibata, Tomoe Komoriya, Shinnosuke Kamei, Hiromichi Asamoto and Masakazu Matsumoto

Fermentation 2024, 10(3), 161; https://doi.org/10.3390/fermentation10030161 - 12 Mar 2024

Viewed by 1003

Abstract

Each year, near 40 million tons of banana peels are discarded around the world. This plant biomass could potentially be utilized for energy production. Simultaneous saccharification and fermentation (SSF) is an effective method for producing biofuels from plant biomasses. Since SSF with enzymatic [...] Read more.

Each year, near 40 million tons of banana peels are discarded around the world. This plant biomass could potentially be utilized for energy production. Simultaneous saccharification and fermentation (SSF) is an effective method for producing biofuels from plant biomasses. Since SSF with enzymatic hydrolysis and fermentation are performed simultaneously in the same reactor, the production process is simpler than most existing methods. Here, we describe isobutanol production using SSF with hydrothermally treated banana peel samples and an Escherichia coli strain able to utilize glucose and xylose to produce isobutanol. To enhance the glucose and xylose concentrations, the reaction conditions for the enzymatic hydrolysis of plant biomass using two kinds of saccharification enzymes were optimized, including the enzyme unit ratio, reaction temperature and sample gram. When the optimized conditions for enzymatic hydrolysis were applied to SSF, the glucose and xylose produced from the hydrothermally treated samples were consumed, producing isobutanol. Moreover, the isobutanol concentration increased with an increasing initial culture pH, reaching 1.27 g/L at pH 6.5, which was consistent with the optimal initial culture pH for isobutanol production by this E. coli strain. Taken together, these results indicate that the established method is potentially useful for industrial isobutanol production. Full article

(This article belongs to the Special Issue Bioconversion of Biomass for Effective Production of Biofuels as Well as Biobased Chemicals and Materials)

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13 pages, 1961 KiB

Open AccessArticle

Enhancement of Anaerobic Digestion of Corn Straw: Effect of Biological Pretreatment and Heating with Bio-Heat Recovery from Pretreatment

by Shanyue Guan, Chao He, Pengfei Li, Panpan Li, Tingting Hou, Zan Gao, Gang Li and Youzhou Jiao

Fermentation 2024, 10(3), 160; https://doi.org/10.3390/fermentation10030160 - 11 Mar 2024

Viewed by 1079

Abstract

Biological pretreatment can promote the degradation of biomass and enhance methane production via the subsequent anaerobic digestion. In addition, a large amount of bio-heat can be generated during the pretreatment process to provide heat for the anaerobic digestion process. In this study, composite [...] Read more.

Biological pretreatment can promote the degradation of biomass and enhance methane production via the subsequent anaerobic digestion. In addition, a large amount of bio-heat can be generated during the pretreatment process to provide heat for the anaerobic digestion process. In this study, composite microorganisms were employed for pretreating corn straw. The impact of different pretreatment times and the heat generated by the pretreatment process on subsequent anaerobic digestion were studied. The results show that the maximum temperature of the pretreatment process was 56.2 °C, obtained on day 6. After 14 days of pretreatment, the degradation rate of the pretreatment group increased by 41% compared with the control group. As a consequence, straws with different pretreatment times were used for anaerobic digestion. The group that underwent 6 days of pretreatment and utilized bio-heat generated from pretreatment achieved the highest cumulative methane production of 401.58 mL/g VS, which was 60.13% higher than in the control group without pretreatment. After 6 days of composite microorganism pretreatment, the group that utilized bio-heat achieved a 29.08% increase in cumulative methane production compared to the group that did not utilize bio-heat. In conclusion, this study highlights the potential of biological pretreatment with composite microorganisms followed by anaerobic digestion using bio-heat as an effective method for treating corn straw. Full article

(This article belongs to the Special Issue Energy Converter: Anaerobic Digestion, 2nd Edition)

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20 pages, 4454 KiB

Open AccessArticle

Influence of Galvanized Steel on Kombucha Fermentation: Weight Loss Measurements, Scanning Electron Microscopy Analysis, Corrosion Activity, and Phytochemical Study

by Najet Mouguech, Patricia Taillandier, Jalloul Bouajila, Regine Basseguy, Mehrez Romdhane and Naceur Etteyeb

Fermentation 2024, 10(3), 159; https://doi.org/10.3390/fermentation10030159 - 11 Mar 2024

Viewed by 842

Abstract

This study aimed to investigate the influence of galvanized steel coupons on black tea kombucha fermentation. As a secondary objective, the corrosion activity of the fermented medium at different stages of fermentation was investigated. The results revealed significant interactions among microorganisms, the metal, [...] Read more.

This study aimed to investigate the influence of galvanized steel coupons on black tea kombucha fermentation. As a secondary objective, the corrosion activity of the fermented medium at different stages of fermentation was investigated. The results revealed significant interactions among microorganisms, the metal, and the fermented medium. On one hand, mass loss measurement, scanning electron microscopy (SEM) analysis, and released zinc and iron ion analysis showed the deterioration of galvanized steel coupons. On the other hand, HPLC-RI analysis showed that the presence of steel coupons improved the kinetics of fermentation. The chemical composition and bioactivity of kombucha were also influenced by the presence of galvanized steel. The results showed the detection of eleven phenolic compounds by HPLC-DAD, including trihydroxyethylrutin, methyl 3,5-dihydroxybenzoate, and ethyl 4-hydroxy-3-cinamate, which were found only in kombucha in the presence of galvanized steel (K+GS). In addition, a total of 53 volatile compounds were detected by GC-MS before and after derivatization, including eleven constituents identified for the first time in K+GS. Concerning antioxidant activity, a higher percentage of inhibition against the DPPH radical was attributed to the ethyl acetate extract found in K+GS (IC₅₀ = 8.6 µg/mL), which could suggest the formation of inhibitors. However, according to the electrochemical findings, the corrosion current density increased threefold during the fermentation process compared to acidified black tea, indicating that corrosion activity was promoted in the kombucha medium and suggesting several competing phenomena between corrosion and inhibition. Full article

(This article belongs to the Special Issue New Fermented Tea: Processing Technology, Microbiology and Health Benefits: 2nd Edition)

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13 pages, 2061 KiB

Open AccessArticle

Enhanced Methanogenesis of Waste-Activated Sludge (WAS) in a Continuous Stirring Tank Reactor with Stealth Electrodes

by Wen He, Dahai Zhang, Lu Zhang, Zhuanyi Ai, Zechong Guo, Tongyi Yang, Linzhi Zhai and Cheng Huang

Fermentation 2024, 10(3), 158; https://doi.org/10.3390/fermentation10030158 - 10 Mar 2024

Viewed by 1040

Abstract

The integration of a microbial electrolysis cell (MEC) is an effective strategy for enhancing the efficiency and stability of an anaerobic digestion (AD) system for energy recovery from waste-activated sludge (WAS). Typically, electrodes are arranged as separate components, potentially disrupting mixing and complicating [...] Read more.

The integration of a microbial electrolysis cell (MEC) is an effective strategy for enhancing the efficiency and stability of an anaerobic digestion (AD) system for energy recovery from waste-activated sludge (WAS). Typically, electrodes are arranged as separate components, potentially disrupting mixing and complicating the reactor configuration, posing challenges for the scaling up of AD-MEC coupling systems. In this study, electrodes were introduced into a continuous stirring tank reactor (CSTR) in a “stealth” manner by integrating them with the inner wall and stirring paddle. This electrode arrangement approach was validated through a sequential batch digestion experiment, resulting in a remarkable 1.5-fold increase in cumulative methane production and a shortened lag period compared to the traditional CSTR with a nonconductive inner wall and stirring paddle. Both the conductive materials (CMs) employed in the electrodes and the electrochemical processes equally contributed to the observed enhancement effect of the electrodes by regulating the evolution of the microbial community within the electrode biofilms, with a specific emphasis on the enrichment of methanogens (primarily Methanobacterium). This research offers a potential avenue to solve the contradiction between the electrode introduction and the mixing operation in AD-MEC coupling systems and to contribute to its future commercial application. Full article

(This article belongs to the Special Issue Treatment of Municipal Wastewater by Anaerobic Biotechnology)

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40 pages, 3737 KiB

Open AccessReview

Penicillium janthinellum: A Potential Producer of Natural Products

by Han Wang, Yanjing Li, Yifei Wang, Ting Shi and Bo Wang

Fermentation 2024, 10(3), 157; https://doi.org/10.3390/fermentation10030157 - 09 Mar 2024

Viewed by 885

Abstract

Penicillium is a kind of common filamentous fungi yielding high levels of secondary metabolites with diverse structures and attractive activities. Among these fungi, Penicillium janthinellum is a potential producer of secondary metabolites whose natural products have been noticed due to their various chemical [...] Read more.

Penicillium is a kind of common filamentous fungi yielding high levels of secondary metabolites with diverse structures and attractive activities. Among these fungi, Penicillium janthinellum is a potential producer of secondary metabolites whose natural products have been noticed due to their various chemical structures and biological activities. This review summarizes the sources, distribution, bioactivities and structural characteristics of compounds isolated from P. janthinellum from 1980 to 2023. A total of 153 natural products have been isolated from P. janthinellum, of which 65 were new compounds. The compounds separated from P. janthinellum exhibit diverse skeletal chemical structures, concentrated in the categories of polyketides (40%), alkaloids (31%) and terpenoids (14%). P. janthinellum-derived compounds display attractive biological activities, such as cytotoxic, antibacterial, antifungal and antiviral activities. These results indicate that P. janthinellum is a potential fungus for producing bioactive secondary metabolites which can be used as precursors for new drugs. Full article

(This article belongs to the Section Microbial Metabolism, Physiology & Genetics)

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14 pages, 2023 KiB

Open AccessReview

Metabolic Oscillation Phenomena in Clostridia Species—A Review

by Annika Tyszak and Lars Rehmann

Fermentation 2024, 10(3), 156; https://doi.org/10.3390/fermentation10030156 - 09 Mar 2024

Viewed by 917

Abstract

Clostridia are interesting candidates for biotechnological applications due to their diverse and unique metabolic abilities. Particularly in continuous fermentation processes, productivity-decreasing metabolic oscillations have been reported in many species. The resulting process instability and reduced productivity can be a serious hurdle for the [...] Read more.

Clostridia are interesting candidates for biotechnological applications due to their diverse and unique metabolic abilities. Particularly in continuous fermentation processes, productivity-decreasing metabolic oscillations have been reported in many species. The resulting process instability and reduced productivity can be a serious hurdle for the development of industrially feasible processes. This review highlights the current state of knowledge about oscillatory metabolic phenomena in Clostridia, including the mechanisms, assumed and proven, behind those oscillations and methods to mitigate the phenomena if applicable. The nature of observed metabolic oscillations in Clostridia is diverse, including a wide range of periods of oscillation and different parameters in which the oscillation is observed. Some phenomena remain to be investigated further, while others are already well understood. However, knowledge of mechanisms is a very valuable asset in overcoming the metabolic oscillation to create a stable process. Full article

(This article belongs to the Special Issue Feature Review Papers in Microbial Metabolism, Physiology & Genetics 2023)

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19 pages, 2530 KiB

Open AccessArticle

Effects of Fermented Goat Milk on Adiposity and Gut Microbiota in a Diet-Induced Obesity Murine Model

by Antonela Marquez, Matías Russo, Carlos Tomei, Patricia Castellano, Edoardo Puglisi, Roxana Medina and Paola Gauffin-Cano

Fermentation 2024, 10(3), 155; https://doi.org/10.3390/fermentation10030155 - 07 Mar 2024

Viewed by 996

Abstract

The administration of goat milk fermented (FGM) with Lactobacillus delbrueckii subsp. indicus CRL1447 and supplemented with different mixes of lactobacilli strains (Mix1: Limosilactobacillus fermentum CRL1446 + Lactiplantibacillus paraplantarum CRL1449 + Lactiplantibacillus paraplantarum CRL1472; Mix2: CRL1446 + CRL1449; Mix3: CRL1446 + CRL1472; and Mix4: [...] Read more.

The administration of goat milk fermented (FGM) with Lactobacillus delbrueckii subsp. indicus CRL1447 and supplemented with different mixes of lactobacilli strains (Mix1: Limosilactobacillus fermentum CRL1446 + Lactiplantibacillus paraplantarum CRL1449 + Lactiplantibacillus paraplantarum CRL1472; Mix2: CRL1446 + CRL1449; Mix3: CRL1446 + CRL1472; and Mix4: CRL1449 + CRL1472) was investigated regarding body weight, metabolic and inflammatory parameters, and gut microbiota (GM) composition in mice fed a high-fat diet (HFD). Body weight gain, adipocyte size, fasting blood glucose, serum triglyceride, and leptin levels were significantly reduced in the group fed FGM+Mix3 compared with the obese mice fed FGM. FGM+Mix2 and FGM+Mix3 modified the GM composition, reversing the dysbiosis caused by the HFD. Although there were no significant changes at the phylum level, the GM composition was significantly changed at the family and genus levels. Results suggest that the administration of FGM+Mix3 improves metabolic and immune profiles in obese mice while positively modulating the GM, therefore attenuating the risk factors associated with obesity. Full article

(This article belongs to the Special Issue Fermentation: 10th Anniversary)

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22 pages, 4825 KiB

Open AccessArticle

Modeling and Optimization of the Culture Medium for Efficient 4′-N-Demethyl-Vicenistatin Production by Streptomyces parvus Using Response Surface Methodology and Artificial-Neural-Network-Genetic-Algorithm

by Zhixin Yu, Hongxin Fu and Jufang Wang

Fermentation 2024, 10(3), 154; https://doi.org/10.3390/fermentation10030154 - 06 Mar 2024

Viewed by 837

Abstract

4′-N-demethyl-vicenistatin is a vicenistatin analogue that has better antitumor activity with promising applications in the pharmaceuticals industry. The harnessing of the complete potential of this compound necessitates a systematic optimization of the culture medium to enable the cost-effective production of 4′-N-demethyl-vicenistatin by Streptomyces [...] Read more.

4′-N-demethyl-vicenistatin is a vicenistatin analogue that has better antitumor activity with promising applications in the pharmaceuticals industry. The harnessing of the complete potential of this compound necessitates a systematic optimization of the culture medium to enable the cost-effective production of 4′-N-demethyl-vicenistatin by Streptomyces parvus SCSIO Mla-L010/ΔvicG. Therefore, in this study, a sequential approach was employed to screen the significant medium compositions, as follows: one-factor-at-a-time (OFAT) and Plackett–Burman designs (PBD) were initially utilized. Cassava starch, glycerol, and seawater salt were identified as the pivotal components influencing 4′-N-demethyl-vicenistatin production. To further investigate the direct and interactive effects of these key components, a three-factor, five-level central composite design (CCD) was implemented. Finally, response surface methodology (RSM) and an artificial-neural-network-genetic-algorithm (ANN-GA) were employed for the modeling and optimization of the medium components to enhance efficient 4′-N-demethyl-vicenistatin production. The ANN-GA model showed superior reliability, achieving the most 4′-N-demethyl-vicenistatin, at 0.1921 g/L, which was 17% and 283% higher than the RSM-optimized and initial medium approaches, respectively. This study represents pioneering work on statistically guided optimization strategies for enhancing 4′-N-demethyl-vicenistatin production through medium optimization. Full article

(This article belongs to the Section Fermentation Process Design)

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19 pages, 3980 KiB

Open AccessArticle

Optimization of Solid-State Fermentation Process of Radix Ranunculi ternate Using Response Surface Method and Addressing Its Antioxidant and Hypoglycemic Activity

by Dingxuan He, Dingyu Duan, Xueyan Lv, Baihui Xiong, Zhuojia Li, Shaojun Zhang, Jing Cai, Xinrong Qiao and Qiong Chen

Fermentation 2024, 10(3), 153; https://doi.org/10.3390/fermentation10030153 - 06 Mar 2024

Viewed by 812

Abstract

Objective: The aim of this study was to optimize the fermentation process of Radix Ranunculi ternate via microbial fermentation and analyze the changes in the contents of the main components, the antioxidant and hypoglycemic capacities of the extract before and after fermentation. Methods: [...] Read more.

Objective: The aim of this study was to optimize the fermentation process of Radix Ranunculi ternate via microbial fermentation and analyze the changes in the contents of the main components, the antioxidant and hypoglycemic capacities of the extract before and after fermentation. Methods: The solid-state fermentation process was optimized using single-factor tests and the response surface method, with the yield of the alcohol extract of R. ternate as an evaluation index. Results: The best fermentation process was optimized using solid-state endophytic fungus fermentation technology as follows: strain addition ratio of Chaetomium globosum/Fusarium equiseti = 1:1, fermentation for 5 d, sieve size of 40 mesh, liquid/material ratio of 0.8:1 mL·g⁻¹, fermentation temperature of 31 °C, and inoculation amount of 7.5%. Under the optimized conditions, the contents of the water-soluble extract and total polysaccharides decreased by 12.71% and 12.95%, respectively. In the fermentation, the contents of the ethanol-soluble extract, flavonoids, saponins, polyphenols, organic acids, and total amino acids of the fermented R. ternate increased by 19.77%, 57.14%, 79.67%, 14.29%, 17.63%, and 3.82%, respectively. The scavenging rate for DPPH, ABTS⁺, and ·OH free radicals and inhibitory rate for α-amylase of the fermented R. ternate also increased by 19.02%, 14.17%, 7.53%, and 34.54%, respectively, compared with the unfermented R. ternate. Conclusions: Solid-state fermentation opens new avenues for the development and application of R. ternate as a natural antioxidant and hypoglycemic food. Full article

(This article belongs to the Section Industrial Fermentation)

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14 pages, 544 KiB

Open AccessArticle

Debaryomyces hansenii Strains from Traditional Chinese Dry-Cured Ham as Good Aroma Enhancers in Fermented Sausage

by Xiaoying Yang, Shan Xiao and Jihui Wang

Fermentation 2024, 10(3), 152; https://doi.org/10.3390/fermentation10030152 - 06 Mar 2024

Viewed by 824

Abstract

In some countries, yeasts are still not allowed in the production of commercially fermented sausages. Therefore, further research is needed on producing fermented meat products using different strains of yeasts. In this study, two strains of Debaryomyces hansenii (D. hansenii Y61 and [...] Read more.

In some countries, yeasts are still not allowed in the production of commercially fermented sausages. Therefore, further research is needed on producing fermented meat products using different strains of yeasts. In this study, two strains of Debaryomyces hansenii (D. hansenii Y61 and Y67) were inoculated in fermented sausages to study their effects as starter cultures. The inoculation of D. hansenii strains affected ripening by decreasing the pH and a_w. The sausages inoculated with Y61 and Y67 exhibited decreases in lipid oxidation of 40.70% and 36.04%, respectively, and Enterobacteriaceae counts of 50% and 100%, respectively. The inoculating yeasts Y61 and Y67 increased the lightness (L*) and redness (a*) of fermented sausages. The D. hansenii-inoculated sausages had higher levels of free amino acids and fatty acids, which improved the digestibility, sensory value, and safety of these sausages. Moreover, the total amount of ester compounds increased by 87.14% and 83.31% in the Y61- and Y67-inoculated groups, respectively, which contributed to the aroma. Better sensory attributes were also found in the sausages inoculated with Y61 and Y67 D. hansenii. Native D. hansenii Y61 and Y67 are, therefore, good starter cultures for fermented sausage production. Together, the results provide data supporting future research and the use of yeast-fermented sausages. Full article

(This article belongs to the Section Fermentation for Food and Beverages)

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16 pages, 3680 KiB

Open AccessArticle

Effect of Biochar in Modulating Anaerobic Digestion Performance and Microbial Structure Community of Different Inoculum Sources

by Jingran Ding, Feng Zhen, Xiaoying Kong, Yunzi Hu, Yi Zhang and Lang Gong

Fermentation 2024, 10(3), 151; https://doi.org/10.3390/fermentation10030151 - 06 Mar 2024

Viewed by 930

Abstract

Biochar has attracted increasing attention as an additive for enhancing the performance of anaerobic digestion (AD), but the effect of biochar on microbial regulatory mechanisms in enhancing AD performance is unclear. To investigate how biochar modulates the process of AD, different inoculum sources [...] Read more.

Biochar has attracted increasing attention as an additive for enhancing the performance of anaerobic digestion (AD), but the effect of biochar on microbial regulatory mechanisms in enhancing AD performance is unclear. To investigate how biochar modulates the process of AD, different inoculum sources including cellulose–peptone–swine inoculum (CPI) and swine manure inoculum (SMI) were designed to determine the effect of biochar on the performance and microbial communities of anaerobic digestion of the feedstock concentration from 1 to 6%. The results showed that the methane yields of CPI seeds were higher 20.3–38.7% than those of SMI seeds without a biochar addition, whereas the biochar addition reduced 5.3 and 23.1% of the corresponding methane yield of CPI and SMI, respectively. The biochar enhances the accumulation of volatile fatty acids (VFAs) and weakens the potential ammonia inhibition by adsorption, and it can improve the degradation rate of organic content of soluble COD for different inoculum sources. Microbial community analyses showed that the biochar addition could facilitate the growth of Bacteroidetes and Clostridiales, and it enriched the relative abundance of hydrogenotrophic methanogens Methanobrevibacter and Methanobacterium. Overall, although the modulation of biochar possessed different effects on the anaerobic digestion performance, it contributed to the stability and degradation efficiency of the digestion system. The recycling implication of biochar is critical to realizing a low-carbon and renewable treatment system for organic wastes. Full article

(This article belongs to the Section Industrial Fermentation)

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12 pages, 2813 KiB

Open AccessArticle

The Biological Role of the S-Layer Produced by Lactobacillus helveticus 34.9 in Cell Protection and Its Probiotic Properties

by Iulia-Roxana Angelescu, Medana Zamfir, Emanuela-Cătălina Ionetic and Silvia-Simona Grosu-Tudor

Fermentation 2024, 10(3), 150; https://doi.org/10.3390/fermentation10030150 - 06 Mar 2024

Viewed by 878

Abstract

Lactobacillus helveticus 34.9 was isolated from a sample of Romanian home-made fermented milk, producing both surface layer proteins and a class III bacteriocin. The present study aimed to investigate the biological and functional role of the S-layer in correlation with its probiotic properties. [...] Read more.

Lactobacillus helveticus 34.9 was isolated from a sample of Romanian home-made fermented milk, producing both surface layer proteins and a class III bacteriocin. The present study aimed to investigate the biological and functional role of the S-layer in correlation with its probiotic properties. The presence of S-layer proteins resulted in various degrees of co-aggregation of L. helveticus 34.9 with pathogens and with other lactic acid bacteria, but the removal of these proteins reduced the co-aggregation with all the tested strains. Moreover, the S-layer proved to be involved in cell wall hydrophobicity and cellular protection during freeze-drying. In the simulated passage through the gastrointestinal tract, S-layer depleted cells exhibited increased vulnerability, with greater viability loss in low pH and pepsin treatment compared to control cells. Subsequently, in the small intestine simulation, these cells lost all viability, underscoring the vital role of extracellular proteins for cell protection. The morphological effects of these treatments were observed by scanning electron microscopy. Severe structural damage was noticed when the S-layer was absent, including loss of cell shape and integrity as well as many ghost cells emptied of their content. Finally, the elimination of surface proteins reduced the interaction between L. helveticus 34.9 and mammalian cells. Full article

(This article belongs to the Section Microbial Metabolism, Physiology & Genetics)

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15 pages, 5154 KiB

Open AccessArticle

Lactic Acid Production by Enterococcus durans Is Improved by Cell Recycling and pH Control

by Raissa Gabriela Martins Reis Barroso, Mônica Caramez Triches Damaso, Fabricio Machado and Sílvia Belém Gonçalves

Fermentation 2024, 10(3), 149; https://doi.org/10.3390/fermentation10030149 - 06 Mar 2024

Viewed by 795

Abstract

Lactic acid bacteria are widely used because they produce lactic acid naturally, are resistant to acidic pH and a wide temperature range, and frequently produce lactic acid as a primary metabolite. In this study, Enterococcus durans isolated from buffalo milk was employed in [...] Read more.

Lactic acid bacteria are widely used because they produce lactic acid naturally, are resistant to acidic pH and a wide temperature range, and frequently produce lactic acid as a primary metabolite. In this study, Enterococcus durans isolated from buffalo milk was employed in lactic acid fermentation with the primary goal of obtaining fermentation parameters for an effective process enabling the use of lactose as an alternative carbon source. Fermentative parameters such as initial concentration of carbon source, dissolved oxygen concentration, cell recycling, and batch with pulse operation mode were studied to find the best conditions for L-(+)-lactic acid production. The association of 20 g·L⁻¹ of lactose with 10 g·L⁻¹ of glucose enabled the best bioconversion to lactic acid. Anaerobiosis did not contribute to increasing lactic acid production. Batch fermentation with cell recycling was the strategy that enhanced lactic acid production and lactose consumption, reaching 26.07 g·L⁻¹, 0.36 g·L⁻¹·h⁻¹ of productivity and yielding about 0.86 g·g⁻¹. It is fundamental to evaluate the parameters of lactic acid fermentation and provide efficient and sustainable production methods. Full article

(This article belongs to the Special Issue Production of Added-Value Products from Renewable Resources and Engineered Cell Factories)

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17 pages, 1399 KiB

Open AccessArticle

Influence of Cryoextraction and Cold Pre-Fermentative Maceration on the Yeast Microbiota and the Volatile Compounds Profile of Sangiovese Wine

by Simona Guerrini, Viola Galli, Silvia Mangani and Lisa Granchi

Fermentation 2024, 10(3), 148; https://doi.org/10.3390/fermentation10030148 - 06 Mar 2024

Viewed by 977

Abstract

Low-temperature treatments can be applied to grapes or must before alcoholic fermentation to enhance the wine’s sensory characteristics. Several studies have shown that such practices have a positive effect on the polyphenol profile of the wine, but only a few surveys have examined [...] Read more.

Low-temperature treatments can be applied to grapes or must before alcoholic fermentation to enhance the wine’s sensory characteristics. Several studies have shown that such practices have a positive effect on the polyphenol profile of the wine, but only a few surveys have examined the effect of these treatments on the yeast microbiota of grapes and wine. Therefore, this study aimed to evaluate how cryoextraction (freezing the grape with liquid nitrogen) and cold pre-fermentative maceration (at 5 °C for 48 h) affect the Saccharomyces and non-Saccharomyces populations during the winemaking process of red grapes, cv Sangiovese, conducted at two temperatures (20 and 30 °C). This research analyzed the concentration of various yeast species, their fermentation abilities, and the resulting wine’s aromatic profile. The Principal Component Analysis performed on yeast concentrations during the fermentations of various wines did not group the experimental wines based on treatment. However, the same groupings were highlighted when the concentrations of the volatile compounds, quantified in the experimental wines, were processed using the same statistical approach. Therefore, cryoextraction and cold pre-fermentative maceration seem to contribute less to the aromatic profile than the yeasts involved in the fermentation process. Full article

(This article belongs to the Special Issue Innovative Strategies for the Management of Wine Fermentations)

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13 pages, 5582 KiB

Open AccessArticle

Diversity of Culturable Yeasts Associated with the Technification Level in the Process of Mezcal Production in the State of Durango

by Sandra Consuelo Martínez-Estrada, José Alberto Narváez-Zapata, Raúl Rodríguez-Herrera, Julio Grijalva-Ávila, José Natividad Gurrola-Reyes, Claudia Patricia Larralde-Corona and Isaías Chairez-Hernández

Fermentation 2024, 10(3), 147; https://doi.org/10.3390/fermentation10030147 - 04 Mar 2024

Viewed by 1150

Abstract

Durango State has the denomination of origin for the production of mezcal, which is made from Agave durangensis, mainly in an artisanal way; therefore, differences in the fermentation process affect the quality of the final product. The main objective of the present [...] Read more.

Durango State has the denomination of origin for the production of mezcal, which is made from Agave durangensis, mainly in an artisanal way; therefore, differences in the fermentation process affect the quality of the final product. The main objective of the present study was to evaluate the diversity of culturable yeasts involved in the artisanal and semi-technified process of mezcal production in the State of Durango. Three distilleries with different production processes were monitored at different fermentation stages (beginning, mid-fermentation, and end of fermentation) in the spring and summer seasons. A greater diversity was found in the distillery of Nombre de Dios in both the spring and summer production seasons (H’ = 1.464 and 1.332, respectively), since it maintains an artisanal production process. In contrast, the distillery of Durango, where a Saccharomyces cerevisiae commercial inoculum is used to start fermentation, presented low diversity indexes (H’ = 0.7903 and 0.6442) and only S. cerevisiae, Kluyveromyces marxianus, and, sporadically, Pichia manshurica were found. Results suggest that the yeast microbiota involved in mezcal fermentation during the different seasons is affected by the type of inoculum; changes include the presence of some species that were only identified during a specific season in alcoholic fermentation, such as Torulaspora delbrueckii and Pichia kluyveri. Full article

(This article belongs to the Section Fermentation for Food and Beverages)

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14 pages, 3428 KiB

Open AccessArticle

Efficient Secretory Expression of Leghemoglobin in Saccharomyces cerevisiae

by Yiyun Huang, Jingwen Zhou, Jianghua Li, Guocheng Du, Jian Chen and Xinrui Zhao

Fermentation 2024, 10(3), 146; https://doi.org/10.3390/fermentation10030146 - 03 Mar 2024

Viewed by 997

Abstract

Leghemoglobin (LegH) is a plant-derived hemoglobin that can be used as a food additive to confer red color and meat flavor to plant-based meat products. Although LegH has been expressed in Saccharomyces cerevisiae, the productivity is low at the shaking-flask level, and [...] Read more.

Leghemoglobin (LegH) is a plant-derived hemoglobin that can be used as a food additive to confer red color and meat flavor to plant-based meat products. Although LegH has been expressed in Saccharomyces cerevisiae, the productivity is low at the shaking-flask level, and the downstream process of purification is complicated. Herein, the intracellular expression of LegH reached 151.2 mg/L through initial promoter modification. Then, the fermentation strategy was optimized, and the titer of LegH reached 544.8 mg/L (5.2 mg/L/OD₆₀₀ per unit yield) in the two-stage fed-batch fermentation in a 5-L fermenter. After the modification of signal peptide and knockout of proteases, the secretory expression of LegH was achieved in recombinant S. cerevisiae, and the final secretory titer of LegH reached 88.5 mg/L at the 5-L fermenter level. Based on the results of this study, the secreted LegH can be widely applied in the fields of food processing and biocatalysis in the future. Full article

(This article belongs to the Section Industrial Fermentation)

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22 pages, 3655 KiB

Open AccessArticle

Potential Use of Lactiplantibacillus plantarum BCC 4352 as a Functional Starter Culture for Fermenting Thai Pork Sausage (Nham)

by Yutthana Kingcha, Laphaslada Pumpuang, Saowalak Adunphatcharaphon, Kanittha Chantarasakha, Pannita Santiyanont, Manadsaree Klomtun, Thitiphorn Janyaphisan, Kittima Kongtong, Natthaporn Phonsatta, Atikorn Panya, Wonnop Visessanguan, Awanwee Petchkongkaew and Weerapong Woraprayote

Fermentation 2024, 10(3), 145; https://doi.org/10.3390/fermentation10030145 - 02 Mar 2024

Viewed by 1096

Abstract

The suitability of Lactiplantibacillus plantarum (L. plantarum) as a functional starter culture in Nham fermentation was investigated, with a focus on evaluating both its probiotic attributes and fermentation capability. L. plantarum BCC 4352 (LpbBCC4352) exhibited colony-associated antimicrobial activity against [...] Read more.

The suitability of Lactiplantibacillus plantarum (L. plantarum) as a functional starter culture in Nham fermentation was investigated, with a focus on evaluating both its probiotic attributes and fermentation capability. L. plantarum BCC 4352 (LpbBCC4352) exhibited colony-associated antimicrobial activity against Kocuria rhizophila, L. plantarum, Latilactobacillus sakei ssp. sakei, and Pediococcus pentosaceus, as well as the zoonotic Streptococcus suis. LpbBCC4352 exhibited impressive acid (pH 2.5) and bile resistance, coupled with notable survival rates in a simulated human digestive model. In addition, the strain is able to utilize fructo-oligosaccharides in simulated human colon conditions. It also displayed robust adhesion to human colon cell monolayers (Caco-2) and gastric mucin. Furthermore, it showed a promising cholesterol reduction ability in the fermentation medium. The safety of LpbBCC4352 for human consumption was confirmed through a hemolytic activity assay and antibiotic susceptibility testing. Moreover, using LpbBCC4352 as a starter culture not only enhanced the firmness of Nham but also ensured consumer satisfaction. The overall findings emphasize the potential use of LpbBCC4352 as a safe and effective functional starter culture, particularly in the production of Nham. Full article

(This article belongs to the Special Issue Probiotics and Prebiotics in Fermented Products)

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