Fermentation

13 pages, 1165 KiB

Open AccessArticle

Residual Gas for Ethanol Production by Clostridium carboxidivorans in a Dual Impeller Stirred Tank Bioreactor (STBR)

by Carolina Benevenuti, Marcelle Branco, Mariana do Nascimento-Correa, Alanna Botelho, Tatiana Ferreira and Priscilla Amaral

Fermentation 2021, 7(3), 199; https://doi.org/10.3390/fermentation7030199 - 21 Sep 2021

Cited by 7 | Viewed by 3587

Abstract

Recycling residual industrial gases and residual biomass as substrates to biofuel production by fermentation is an important alternative to reduce organic wastes and greenhouse gases emission. Clostridium carboxidivorans can metabolize gaseous substrates as CO and CO₂ to produce ethanol and higher alcohols [...] Read more.

Recycling residual industrial gases and residual biomass as substrates to biofuel production by fermentation is an important alternative to reduce organic wastes and greenhouse gases emission. Clostridium carboxidivorans can metabolize gaseous substrates as CO and CO₂ to produce ethanol and higher alcohols through the Wood-Ljungdahl pathway. However, the syngas fermentation is limited by low mass transfer rates. In this work, a syngas fermentation was carried out in serum glass bottles adding different concentrations of Tween® 80 in ATCC® 2713 culture medium to improve gas-liquid mass transfer. We observed a 200% increase in ethanol production by adding 0.15% (v/v) of the surfactant in the culture medium and a 15% increase in biomass production by adding 0.3% (v/v) of the surfactant in the culture medium. The process was reproduced in stirred tank bioreactor with continuous syngas low flow, and a maximum ethanol productivity of 0.050 g/L.h was achieved. Full article

(This article belongs to the Special Issue Biofuels Production and Processing Technology)

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12 pages, 1844 KiB

Open AccessArticle

Addressing Enzymatic Clarification Challenges of Muscat Grape Juice

by Matt Ridge, Stephan Sommer and Daniel A. Dycus

Fermentation 2021, 7(3), 198; https://doi.org/10.3390/fermentation7030198 - 18 Sep 2021

Cited by 3 | Viewed by 4176

Abstract

Winemakers use technical enzymes to assist with clarification, extraction, and other processes in winemaking. In some cases, enzyme mixes are found to be ineffective for a variety of reasons. This study characterizes difficult-to-clarify juices from the Muscat family, examines the effects of pasteurization, [...] Read more.

Winemakers use technical enzymes to assist with clarification, extraction, and other processes in winemaking. In some cases, enzyme mixes are found to be ineffective for a variety of reasons. This study characterizes difficult-to-clarify juices from the Muscat family, examines the effects of pasteurization, and classifies these juices based on cultivar, harvest date, geographical location, and harvesting technique. In addition to studying the chemical compositions of different Muscat juices, enzyme testing was performed by creating enzyme cocktails and evaluating their functionality. The data suggest a distinct matrix effect on juice clarification that can be influenced during juice processing. Berry proteins, polysaccharides, and native enzymes play an important role during the clarification process, influencing the efficiency of technical enzymes. On the other side, high macromolecule extraction from the grape material, through excessive shearing forces in machine-harvested and processed fruit, for example, can have a negative effect, especially in ripe and overripe grape material. Based on these findings, the winemaking strategy and use of technical enzymes need to be adapted to the incoming grapes. Besides adjusting the mechanical forces to the level of ripeness, avoiding native fermentation prior to clarification should be prioritized. The enzyme mixes developed and tested in these experiments show a high degree of efficiency in the majority of juices that were evaluated. Full article

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

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16 pages, 2037 KiB

Open AccessArticle

Improvement of Biomethane Production from Organic Fraction of Municipal Solid Waste (OFMSW) through Alkaline Hydrogen Peroxide (AHP) Pretreatment

by Alessio Siciliano, Carlo Limonti and Giulia Maria Curcio

Fermentation 2021, 7(3), 197; https://doi.org/10.3390/fermentation7030197 - 17 Sep 2021

Cited by 10 | Viewed by 2536

Abstract

The organic fraction resulting from the separate collection of municipal solid waste (OFMSW) is an abundant residue exploitable for biofuel production. Anaerobic digestion (AD) is one of the most attractive technologies for the treatment of organic wastes thanks to the generation of biogas [...] Read more.

The organic fraction resulting from the separate collection of municipal solid waste (OFMSW) is an abundant residue exploitable for biofuel production. Anaerobic digestion (AD) is one of the most attractive technologies for the treatment of organic wastes thanks to the generation of biogas with a high methane content. However, because of its complex composition, the direct digestion of OFMSW can be less effective. To overcome these difficulties, many pretreatments are under development. In this work, the efficacy of alkaline hydrogen peroxide (AHP) oxidation was assessed for the first time as a pretreatment of OFMSW to enhance its anaerobic biodegradability. In this regard, many AHP batch tests were executed at pH 9 and by changing the peroxide dosages up to 1 g_H2O2/g_COD, under room temperature and pressure conditions. Afterwards, biomethane potential tests (BMP) were conducted to evaluate the performance of anaerobic digestion both on raw and pretreated OFMSW. The pretreatment tests demonstrated that AHP induces only a weak reduction in the organic load, reaching a maximum COD removal of about 28%. On the other hand, notable productions of volatile fatty acids (VFA) were found. In fact, by applying a peroxide dose of just 0.025 g_H2O2/g_COD, there was a doubling in VFA concentration, which increased by five times with the highest H₂O₂ amount. These results indicate that AHP mainly causes the conversion of complex organic substrates into easily degradable compounds. This conversion made it possible to achieve much better performance during the BMP tests conducted with the pretreated waste compared to that carried out on fresh OFMSW. Indeed, a low methane production of just 37.06 mL_CH4/g_TS was detected on raw OFMSW. The cumulated CH₄ production in the pretreated samples increased in response to the increase in H₂O₂ dosage applied during AHP. Maximum specific productions of about 463.7 mL_CH4/g_TS and 0.31 L_CH4/g_CODremoved were calculated on mixtures subjected to AHP. On these samples, the satisfactory evolution of AD was confirmed by the process parameters calculated by modeling the cumulated CH₄ curves through a new proposed formulation of the Gompertz equation. Full article

(This article belongs to the Special Issue Biomass and Waste Valorization)

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13 pages, 274 KiB

Open AccessArticle

Manipulation of In Vitro Ruminal Fermentation and Feed Digestibility as Influenced by Yeast Waste-Treated Cassava Pulp Substitute Soybean Meal and Different Roughage to Concentrate Ratio

by Gamonmas Dagaew, Anusorn Cherdthong, Sawitree Wongtangtintharn, Metha Wanapat and Chanon Suntara

Fermentation 2021, 7(3), 196; https://doi.org/10.3390/fermentation7030196 - 17 Sep 2021

Cited by 11 | Viewed by 3467

Abstract

Cassava pulp (CS) is high in fiber and low in protein; hence, improving the nutritive value of CS is required to increase its contribution to enhancing ruminant production. The present work hypothesized that CS quality could be enhanced by fermentation with yeast waste [...] Read more.

Cassava pulp (CS) is high in fiber and low in protein; hence, improving the nutritive value of CS is required to increase its contribution to enhancing ruminant production. The present work hypothesized that CS quality could be enhanced by fermentation with yeast waste (YW), which can be used to replace soybean meal (SBM), as well as lead to improved feed utilization in ruminants. Thus, evaluation of in vitro ruminal fermentation and feed digestibility, as influenced by YW-treated CS and different roughage (R) to concentrate (C) ratios, was elucidated. The design of the experiment was a 5 × 3 factorial arrangement in a completely randomized design. Each treatment contained three replications and three runs. The first factor was replacing SBM with CS fermented with YW (CSYW) in a concentrate ratio at 100:0, 75:25, 50:50, 25:75, and 0:100, respectively. The second factor was R:C ratios at 70:30, 50:50, and 30:70. The level of CSYW showed significantly higher (p < 0.01) gas production from the insoluble fraction (b), potential extent of gas production (a + b), and cumulative gas production at 96 h than the control group (p < 0.05). There were no interactions among the CSYW and R:C ratio on the in vitro digestibility (p > 0.05). Furthermore, increasing the amount of CSYW to replace SBM up to 75% had no negative effect on in vitro neutral detergent fiber degradability (IVNDFD) (p > 0.05) while replacing CSWY at 100% could reduce IVNDFD (p > 0.05). The bacterial population in the rumen was reduced by 25.05% when CSYW completely replaced SBM (p < 0.05); however, 75% of CSWY in the diet did not change the bacterial population (p > 0.05). The concentration of propionate (C3) decreased upon an increase in the CSYW level, which was lowest with the replacement of SBM by CSYW up to 75%. However, various R:C ratios did not influence total volatile fatty acids (VFAs), and the proportion of VFAs (p > 0.05), except the concentration of C3, increased when the proportion of a concentrate diet increased (p < 0.05). In conclusion, CSYW could be utilized as a partial replacement for SBM in concentrate diets up to 75% without affecting gas kinetics, ruminal parameters, or in vitro digestibility. Full article

(This article belongs to the Special Issue Yeast Biotechnology 5.0)

16 pages, 1956 KiB

Open AccessArticle

Probiotic and Antioxidant Properties of Lactic Acid Bacteria Isolated from Indigenous Fermented Tea Leaves (Miang) of North Thailand and Promising Application in Synbiotic Formulation

by Kridsada Unban, Wirunya Chaichana, Sasitorn Baipong, Aliyu Dantani Abdullahi, Apinun Kanpiengjai, Kalidas Shetty and Chartchai Khanongnuch

Fermentation 2021, 7(3), 195; https://doi.org/10.3390/fermentation7030195 - 16 Sep 2021

Cited by 28 | Viewed by 5526

Abstract

Miang, a traditional fermented tea from Northern Thailand, potentially hosts beneficial probiotic bacteria. A total of 133 isolates of lactic acid bacteria (LAB) isolated from Miang were evaluated for probiotic potential. Among them, 5 strains showed high tolerance to bile and acidic conditions [...] Read more.

Miang, a traditional fermented tea from Northern Thailand, potentially hosts beneficial probiotic bacteria. A total of 133 isolates of lactic acid bacteria (LAB) isolated from Miang were evaluated for probiotic potential. Among them, 5 strains showed high tolerance to bile and acidic conditions and were selected for further evaluation. All selected strains showed inhibitory activity against human pathogens, including Bacillus cereus, Staphylococcus aureus, and Salmonella ser. Typhimurium. Nucleotide sequences analysis of the 16S rRNA gene revealed that 3 isolates were identified as Lactobacillus pentosus; the remaining were L. plantarum and Pediococcus pentosaceus, respectively. All 5 strains showed a high survival rate of more than 90% when exposed to simulated gastrointestinal conditions and were also susceptible to antibiotics such as erythromycin, tetracycline, and gentamycin, and resistant to vancomycin, streptomycin, and polymycin. In addition, the selected isolates exhibited different degrees of cell surface hydrophobicity (58.3–92.9%) and auto-aggregation (38.9–46.0%). The antioxidant activity reflected in DPPH scavenging activities of viable cells and their cell-free culture supernatants (CFCS) were also found in selected LAB isolates. Moreover, selected LAB isolates showed ability to grow on commercial prebiotics (GOS, FOS or XOS). The preliminary study of spray-drying using cyclodextrin as thermoprotectant suggested that all strains can be designed as a powdered formulation. L. pentosus A14-6 was the best strain, with high tolerance against simulated gastrointestinal conditions, high cell surface hydrophobicity, effective response to tested commercial oligosaccharides, especially XOS, and the highest cell antioxidant properties. L. pentosus A14-6 was therefore targeted for further applications in food and synbiotic applications. Full article

(This article belongs to the Special Issue Fermented Foods and Microbes Related to Health)

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21 pages, 22083 KiB

Open AccessArticle

Bioethanol Production from Sugarcane Press-Mud: Assessment of the Fermentation Conditions to Reduce Fusel Alcohol

by Nestor Sanchez, Martha Cobo, David Rodriguez-Fontalvo, Miguel Ángel Uribe-Laverde and Ruth Y. Ruiz-Pardo

Fermentation 2021, 7(3), 194; https://doi.org/10.3390/fermentation7030194 - 15 Sep 2021

Cited by 6 | Viewed by 5154

Abstract

Within a biorefinery context, bioethanol is a promising platform molecule since it can be used as raw material to produce a wide spectrum of valuable industrial products such as H₂ and light olefins. However, the presence of impurities limits the conversion of [...] Read more.

Within a biorefinery context, bioethanol is a promising platform molecule since it can be used as raw material to produce a wide spectrum of valuable industrial products such as H₂ and light olefins. However, the presence of impurities limits the conversion of bioethanol in these products. Herein, we aimed to determine the proper pretreatment and fermentation conditions to yield bioethanol with a low content of impurities, such as 3-methyl-1-butanol, by using sugarcane press-mud as feedstock. To do so, a Box-Behnken methodology was employed to select proper pretreatment and fermentation conditions. Factors assessed were temperature, stirring, and pH during fermentation of hydrolysates coming from two different pretreatment methods named as hydrothermal and acid hydrolysis. Results showed that the fermentation temperature should be kept between 26–30 °C to assure at least 91 g/L ethanol. The fusel alcohol content would be reduced by 22% at 30 °C, pH = 4.5, and 200 rpm if sugarcane press-mud is pretreated under acid hydrolysis conditions (T = 130 °C, t = 1 h, 16 g HNO₃/kg solid). Further studies should aim to integrate these conditions within a biorefinery concept to yield valuable products such as H₂ and ethylene. Full article

(This article belongs to the Section Fermentation Process Design)

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15 pages, 1113 KiB

Open AccessEditor’s ChoiceArticle

Use of Lachancea thermotolerans for Biological vs. Chemical Acidification at Pilot-Scale in White Wines from Warm Areas

by Cristian Vaquero, Pedro Miguel Izquierdo-Cañas, Adela Mena-Morales, L. Marchante-Cuevas, José María Heras and Antonio Morata

Fermentation 2021, 7(3), 193; https://doi.org/10.3390/fermentation7030193 - 15 Sep 2021

Cited by 20 | Viewed by 3515

Abstract

Climate change is affecting vineyards, resulting in grapes with a low acidity a high pH and sugar at harvest time. The most common procedure so far to improve the acidity and reduce the final pH of wines is to use tartaric acid, but [...] Read more.

Climate change is affecting vineyards, resulting in grapes with a low acidity a high pH and sugar at harvest time. The most common procedure so far to improve the acidity and reduce the final pH of wines is to use tartaric acid, but wine can also be acidified microbiologically using Lachancea thermotolerans yeasts, a natural bio-tool that acidifies gradually during the first stage/days of fermentation. Two strains of L. thermotolerans were compared with one Saccharomyces cerevisiae at a pilot-scale under similar fermentation conditions and in duplicate. A sequential inoculation was performed on the third day for the non-Saccharomyces, producing only about 1 g/L of lactic acid, which was suitable for comparison with the Saccharomyces, to which 1.5 g/L of tartaric acid had been added to lower the final pH. The three fermentations ended with a total acidity without significant differences. A significant and normal feature of the L. thermotolerans yeasts is their higher propane-1,2,3-triol production, which was observed in the Laktia yeast, and the acetic acid was <0.3 g/L. The amount of volatile metabolites was generally higher for non-Saccharomyces and the increase was seen in carbonyl compounds, organic acids, lactones, fumaric compounds, and phenols. Finally, the sensory analysis showed that there were hardly any significant differences, even though the non-Saccharomyces had a higher quantity of volatile metabolites, which could lead to a good acceptance of the product, since biological acidification was used, generating a more natural product. Full article

(This article belongs to the Special Issue Enological Repercussions of Non-Saccharomyces Species 3.0)

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12 pages, 2014 KiB

Open AccessArticle

Indigenous Yeast, Lactic Acid Bacteria, and Acetic Acid Bacteria from Cocoa Bean Fermentation in Indonesia Can Inhibit Fungal-Growth-Producing Mycotoxins

by Endang Sutriswati Rahayu, Rokhmat Triyadi, Rosyida N. B. Khusna, Titiek Farianti Djaafar, Tyas Utami, Tri Marwati and Retno Utami Hatmi

Fermentation 2021, 7(3), 192; https://doi.org/10.3390/fermentation7030192 - 14 Sep 2021

Cited by 15 | Viewed by 8648

Abstract

Cocoa bean fermentation is an important process in the manufacturing of cocoa products. It involves microbes, such as lactic acid bacteria, yeast, and acetic acid bacteria. The presence of mold in cocoa bean fermentation is undesired, as it reduces the quality and may [...] Read more.

Cocoa bean fermentation is an important process in the manufacturing of cocoa products. It involves microbes, such as lactic acid bacteria, yeast, and acetic acid bacteria. The presence of mold in cocoa bean fermentation is undesired, as it reduces the quality and may produce mycotoxins, which can cause poisoning and death. Aspergillus niger is a fungus that produces ochratoxin A, which is often found in dried agricultural products such as seeds and cereals. In this study, we applied indigenous Candida famata HY-37, Lactobacillus plantarum HL-15, and Acetobacter spp. HA-37 as starter cultures for cocoa bean fermentation. We found that the use of L. plantarum HL-15 individually or in combination Candida famata HY-37, Lactobacillus plantarum HL-15, and Acetobacter spp. HA-37 as a starter for cocoa bean fermentation can inhibit the growth of A. niger YAC-9 and the synthesis of ochratoxin A during fermentation and drying. With biological methods that use indigenous Lactobacillus plantarum HL-15 individually or in combination with Candida famata HY-37 and Acetobacter spp. HA-37, we successfully inhibited contamination by ochratoxin-A-producing fungi. Thus, the three indigenous microbes should be used in cocoa bean fermentation to inhibit the growth of fungi that produce mycotoxins and thus improve the quality. Full article

(This article belongs to the Special Issue Food Fermentation for Better Nutrition, Health and Sustainability)

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16 pages, 2516 KiB

Open AccessArticle

Pretreatment of Corn Stover Using an Extremely Low-Liquid Ammonia (ELLA) Method for the Effective Utilization of Sugars in Simultaneous Saccharification and Fermentation (SSF) of Ethanol

by Tin Diep Trung Le, Vi Phuong Nguyen Truong, My Thi Tra Ngo, Tae Hyun Kim and Kyeong Keun Oh

Fermentation 2021, 7(3), 191; https://doi.org/10.3390/fermentation7030191 - 14 Sep 2021

Cited by 8 | Viewed by 3014

Abstract

Extremely low-liquid ammonia (ELLA) pretreatment using aqueous ammonia was investigated in order to enhance the enzymatic saccharification of corn stover and subsequent ethanol production. In this study, corn stover was treated with an aqueous ammonia solution at different ammonia loading rates (0.1, 0.2, [...] Read more.

Extremely low-liquid ammonia (ELLA) pretreatment using aqueous ammonia was investigated in order to enhance the enzymatic saccharification of corn stover and subsequent ethanol production. In this study, corn stover was treated with an aqueous ammonia solution at different ammonia loading rates (0.1, 0.2, and 0.3 g NH₃/g biomass) and various liquid-to-solid (L/S) ratios (0.55, 1.12, and 2.5). The ELLA pretreatment was conducted at elevated temperatures (90–150 °C) for an extended period (24–120 h). Thereafter, the pretreated material was saccharified by enzyme digestion and subjected to simultaneous saccharification and fermentation (SSF) tests. The effects of key parameters on both glucan digestibility and xylan digestibility were analyzed using analysis of variance (ANOVA). Under optimal pretreatment conditions (L/S = 2.5, 0.1 g-NH₃/g-biomass, 150 °C), 81.2% glucan digestibility and 61.1% xylan digestibility were achieved. The highest ethanol yield achieved on the SSF tests was 85.4%. The ethanol concentration was 14.5 g/L at 96 h (pretreatment conditions: liquid-to-solid ratio (L/S) = 2.5, 0.1 g-NH₃/g-biomass, 150 °C, 24 h. SSF conditions: microorganism Saccharomyces cerevisiae (D₅A), 15 FPU/g-glucan, CTech2, 3% w/v glucan, 37 °C, 150 rpm). Full article

(This article belongs to the Special Issue Ethanol and Value-Added Co-products 3.0)

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15 pages, 3840 KiB

Open AccessArticle

Effect of Microbial Enzymes on the Changes in the Composition and Microstructure of Hydrolysates from Poultry By-Products

by Svetlana Merenkova, Oksana Zinina, Irina Lykasova, Alexander Kuznetsov and Tatyana Shnyakina

Fermentation 2021, 7(3), 190; https://doi.org/10.3390/fermentation7030190 - 12 Sep 2021

Cited by 4 | Viewed by 2478

Abstract

Poultry by-products are promising for the production of protein hydrolysates by enzymatic hydrolysis. The aim of the study is to research the effect of bacterial concentrates on the changes in the amino acid composition and microstructure of poultry by-products during fermentation. Hydrolysis of [...] Read more.

Poultry by-products are promising for the production of protein hydrolysates by enzymatic hydrolysis. The aim of the study is to research the effect of bacterial concentrates on the changes in the amino acid composition and microstructure of poultry by-products during fermentation. Hydrolysis of the gizzards and combs was carried out with a liquid concentrate of bifidobacteria and propionic acid bacteria. As a result of microstructural study of fermented by-products, a decrease in the perception of histological dyes, poor visualization of the cell elements and blurring of the connective tissue matrix were established. During morphometric analyses, we found a reduction in the specific area of connective tissue, the diameter of collagen fibers and the thickness of muscle fibers. A significant effect of the fermentation on the particle size distribution was noted; samples hydrolyzed by microbial enzymes were characterized by a high uniformity of particle sizes and a large number of small particles. Our research revealed an increase in the concentration of free amino acids in the hydrolysates during the fermentation period. The results of biochemical and microscopic analysis confirm the good hydrolysability of hen combs and gizzards under the action of microbial enzymes. Full article

(This article belongs to the Special Issue Value-Added Co-products from Industrial Fermentation)

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13 pages, 658 KiB

Open AccessArticle

Application of a Biosurfactant Produced by Bacillus cereus UCP 1615 from Waste Frying Oil as an Emulsifier in a Cookie Formulation

by Italo J. B. Durval, Beatriz G. Ribeiro, Jaciana S. Aguiar, Raquel D. Rufino, Attilio Converti and Leonie A. Sarubbo

Fermentation 2021, 7(3), 189; https://doi.org/10.3390/fermentation7030189 - 12 Sep 2021

Cited by 23 | Viewed by 3322

Abstract

Biosurfactants have attracted increasing interest from the food industry due to their emulsifying, foaming and solubilizing properties. However, the industrial use of microbial biosurfactants has been hampered by the high production costs related mainly to the use of expensive substrates. The search for [...] Read more.

Biosurfactants have attracted increasing interest from the food industry due to their emulsifying, foaming and solubilizing properties. However, the industrial use of microbial biosurfactants has been hampered by the high production costs related mainly to the use of expensive substrates. The search for low-cost alternative substrates is one of the strategies adopted to overcome this problem. In the present study, a biosurfactant produced by Bacillus cereus UCP1615 by fermentation in a medium supplemented with waste frying soybean oil as a low-cost substrate was evaluated as a bioemulsifier for the production of cookies. The biosurfactant was evaluated for its emulsifying capacity against different vegetable oils, antioxidant activity and toxicity, demonstrating favorable results for use in food. In particular, it showed satisfactory antioxidant activity at the tested concentrations and no cytotoxicity to the L929 (mouse fibroblast) and Vero (monkey kidney epithelial) cell lines using the MTT assay. The biosurfactant was then added at different concentrations (0.25%, 0.5% and 1%) to a standard cookie dough formulation to evaluate the physicochemical characteristics of the product. Cookies formulated with the biosurfactant exhibited similar energy and physical characteristics to those obtained with the standard formulation but with a lower moisture content. The biosurfactant also ensured a good preservation of the cookie texture after 45 days of storage. These results suggest that the biosurfactant has a potential application as a green emulsifier in accordance with the demands of the current market for biocompatible products. Full article

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

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14 pages, 1507 KiB

Open AccessArticle

Stress Resistance and Adhesive Properties of Commercial Flor and Wine Strains, and Environmental Isolates of Saccharomyces cerevisiae

by Michail A. Eldarov, Daria A. Avdanina, Elena Ivanova, Maksim Y. Shalamitskiy, Tatiana N. Tanashchuk, Tatiana Vybornaya, Nikolai V. Ravin, Svetlana A. Kishkovskaya and Andrey V. Mardanov

Fermentation 2021, 7(3), 188; https://doi.org/10.3390/fermentation7030188 - 11 Sep 2021

Cited by 2 | Viewed by 2585

Abstract

Flor strains of Saccharomyces cerevisiae represent a special group of yeasts used for producing biologically aged wines. We analyzed the collection of commercial wine and flor yeast strains, as well as environmental strains isolated from the surface of grapes growing in vineyards, for [...] Read more.

Flor strains of Saccharomyces cerevisiae represent a special group of yeasts used for producing biologically aged wines. We analyzed the collection of commercial wine and flor yeast strains, as well as environmental strains isolated from the surface of grapes growing in vineyards, for resistance to abiotic stresses, adhesive properties, and the ability to form a floating flor. The degree of resistance of commercial strains to ethanol, acetaldehyde, and hydrogen peroxide was generally not higher than that of environmental isolates, some of which had high resistance to the tested stress agents. The relatively low degree of stress resistance of flor strains can be explained both by the peculiarities of their adaptive mechanisms and by differences in the nature of their exposure to various types of stress in the course of biological wine aging and under the experimental conditions we used. The hydrophobicity and adhesive properties of cells were determined by the efficiency of adsorption to polystyrene and the distribution of cells between the aqueous and organic phases. Flor strains were distinguished by a higher degree of hydrophobicity of the cell surface and an increased ability to adhere to polystyrene. A clear correlation between biofilm formation and adhesive properties was also observed for environmental yeast isolates. The overall results of this study indicate that relatively simple tests for cell hydrophobicity can be used for the rapid screening of new candidate flor strains in yeast culture collections and among environmental isolates. Full article

(This article belongs to the Special Issue New Insight and Current Trends in Oenological Microbiology)

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7 pages, 196 KiB

Open AccessEditorial

Advances in Wine Fermentation

by Sergi Maicas

Fermentation 2021, 7(3), 187; https://doi.org/10.3390/fermentation7030187 - 10 Sep 2021

Cited by 20 | Viewed by 23571

Abstract

Fermentation is a well-known natural process that has been used by humanity for thousands of years, with the fundamental purpose of making alcoholic beverages such as wine, and also other non-alcoholic products. From a strictly biochemical point of view, fermentation is a process [...] Read more.

Fermentation is a well-known natural process that has been used by humanity for thousands of years, with the fundamental purpose of making alcoholic beverages such as wine, and also other non-alcoholic products. From a strictly biochemical point of view, fermentation is a process of central metabolism in which an organism converts a carbohydrate, such as starch or sugar, into an alcohol or an acid. The fermentation process turns grape juice (must) into wine. This is a complex chemical reaction whereby the yeast interacts with the sugars (glucose and fructose) in the must to create ethanol and carbon dioxide. Fermentation processes to produce wines are traditionally carried out with Saccharomyces cerevisiae strains, the most common and commercially available yeast, and some lactic acid bacteria. They are well-known for their fermentative behavior and technological characteristics, which allow obtaining products of uniform and standard quality. However, fermentation is influenced by other factors as well. The initial sugar content of the must and the fermentation temperature are also crucial to preserve volatile aromatics in the wine and retain fruity characters. Finally, once fermentation is completed, and most of the yeast dies, wine evolution continues until the production of the final product. Full article

(This article belongs to the Special Issue Advances in Wine Fermentation)

15 pages, 4305 KiB

Open AccessArticle

Anti-Osteoporotic Activity of Pueraria lobata Fermented with Lactobacillus paracasei JS1 by Regulation of Osteoblast Differentiation and Protection against Bone Loss in Ovariectomized Mice

by Seon Yu Kim, Hee-Ju Lee, Taehyun Kim, Yeong-Geun Lee, Jeong Eun Kwon and Se Chan Kang

Fermentation 2021, 7(3), 186; https://doi.org/10.3390/fermentation7030186 - 9 Sep 2021

Cited by 3 | Viewed by 2771

Abstract

Osteoporosis is the most common bone disease associated with low bone mineral density. It is the process of bone loss and is most commonly caused by decreased estrogen production in women, particularly after menopause. Pueraria lobata, which contains various metabolites, especially isoflavone, is [...] Read more.

Osteoporosis is the most common bone disease associated with low bone mineral density. It is the process of bone loss and is most commonly caused by decreased estrogen production in women, particularly after menopause. Pueraria lobata, which contains various metabolites, especially isoflavone, is widely known as regulator for bone mineral contents. In this study, the effects of the P. lobata extract (PE) with or without fermentation with Lactobacillus paracasei JS1 (FPE) on osteoporosis were investigated in vitro and in vivo. The effects of PE and FPE on human osteoblastic MG63 cells, RAW 264.7 cells, and ovariectomized (OVX)-induced model mice were analyzed at various ratios. We found that FPE increased calcium deposition and inhibited bone resorption by in vitro assay. Furthermore, treatment with PE and FPE has significantly restored destroyed trabecular bone in the OVX-induced bone loss mouse model. Overall, FPE demonstrated bioactivity to prevent bone loss by decreasing bone turnover. Full article

(This article belongs to the Special Issue Fermented Foods and Microbes Related to Health)

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15 pages, 2482 KiB

Open AccessArticle

Citric Acid Influences the Dynamics of the Fermentation Quality, Protease Activity and Microbial Community of Mulberry Leaf Silage

by Dekui Chen, Wei Zhou, Xiang Guo, Mingyang Zheng, Xiaoyang Chen and Qing Zhang

Fermentation 2021, 7(3), 185; https://doi.org/10.3390/fermentation7030185 - 9 Sep 2021

Cited by 5 | Viewed by 3596

Abstract

Mulberry (Morus alba) leaves has performed well as a high-quality protein supplement for livestock and enriches the edible resources of livestock. However, the harvest of mulberry leaves is seasonal and occurs mainly during the rainy season in southeast China; therefore, humid [...] Read more.

Mulberry (Morus alba) leaves has performed well as a high-quality protein supplement for livestock and enriches the edible resources of livestock. However, the harvest of mulberry leaves is seasonal and occurs mainly during the rainy season in southeast China; therefore, humid and sultry weather causes serious losses of mulberry leaf biomass, which pose a challenge for the preservation of mulberry leaves. In this study, we used the silage fermentation method to preserve mulberry leaves and investigated the effects of citric acid on the silage quality of mulberry leaves. Mulberry leaves were ensiled with or without 1% citric acid and 2% citric acid. The chemical composition, protein fraction and microbial community of mulberry leaf silages were analyzed. The results showed that the silage treated with citric acid had a higher dry matter recovery and lactic acid content and a lower acetic acid content, non-protein nitrogen content and ammonia-N content; citric acid also inhibited the activities of carboxypeptidase and aminopeptidase. Moreover, citric acid increased Lactobacillus abundance in silages and decreased the abundance of undesired microorganisms, such as Enterobacter. In summary, the addition of citric acid improved the fermentation quality of mulberry leaf silages, with 2% citric acid being more effective than 1% citric acid. Full article

(This article belongs to the Special Issue Fermentation and Bioactive Metabolites 3.0)

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14 pages, 1126 KiB

Open AccessArticle

A Comprehensive Bioprocessing Approach to Foster Cheese Whey Valorization: On-Site β-Galactosidase Secretion for Lactose Hydrolysis and Sequential Bacterial Cellulose Production

by Iliada K. Lappa, Vasiliki Kachrimanidou, Aikaterini Papadaki, Anthi Stamatiou, Dimitrios Ladakis, Effimia Eriotou and Nikolaos Kopsahelis

Fermentation 2021, 7(3), 184; https://doi.org/10.3390/fermentation7030184 - 8 Sep 2021

Cited by 13 | Viewed by 3693

Abstract

Cheese whey (CW) constitutes a dairy industry by-product, with considerable polluting impact, related mostly with lactose. Numerous bioprocessing approaches have been suggested for lactose utilization, however, full exploitation is hindered by strain specificity for lactose consumption, entailing a confined range of end-products. Thus, [...] Read more.

Cheese whey (CW) constitutes a dairy industry by-product, with considerable polluting impact, related mostly with lactose. Numerous bioprocessing approaches have been suggested for lactose utilization, however, full exploitation is hindered by strain specificity for lactose consumption, entailing a confined range of end-products. Thus, we developed a CW valorization process generating high added-value products (crude enzymes, nutrient supplements, biopolymers). First, the ability of Aspergillus awamori to secrete β-galactosidase was studied under several conditions during solid-state fermentation (SSF). Maximum enzyme activity (148 U/g) was obtained at 70% initial moisture content after three days. Crude enzymatic extracts were further implemented to hydrolyze CW lactose, assessing the effect of hydrolysis time, temperature and initial enzymatic activity. Complete lactose hydrolysis was obtained after 36 h, using 15 U/mL initial enzymatic activity. Subsequently, submerged fermentations were performed with the produced hydrolysates as onset feedstocks to produce bacterial cellulose (5.6–7 g/L). Our findings indicate a novel approach to valorize CW via the production of crude enzymes and lactose hydrolysis, aiming to unfold the output potential of intermediate product formation and end-product applications. Likewise, this study generated a bio-based material to be further introduced in novel food formulations, elaborating and conforming with the basic pillars of circular economy. Full article

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

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17 pages, 3212 KiB

Open AccessArticle

Evaluation of Autochthonous Non-Saccharomyces Yeasts by Sequential Fermentation for Wine Differentiation in Galicia (NW Spain)

by Pilar Blanco, David Castrillo, María José Graña, María José Lorenzo and Elvira Soto

Fermentation 2021, 7(3), 183; https://doi.org/10.3390/fermentation7030183 - 7 Sep 2021

Cited by 11 | Viewed by 2634

Abstract

Non-Saccharomyces yeasts constitute a useful tool in winemaking because they secrete hydrolytic enzymes and produce metabolites that enhance wine quality; in addition, their ability to reduce alcohol content and/or to increase acidity can help to mitigate the effects of climatic change on [...] Read more.

Non-Saccharomyces yeasts constitute a useful tool in winemaking because they secrete hydrolytic enzymes and produce metabolites that enhance wine quality; in addition, their ability to reduce alcohol content and/or to increase acidity can help to mitigate the effects of climatic change on wines. The purpose of this study was to evaluate the oenological traits of non-Saccharomyces yeast strains autochthonous from Galicia (NW Spain). To do that, we carried out sequential fermentation using 13 different species from the yeast collection of Estación de Viticultura e Enoloxía de Galicia (Evega) and Saccharomyces cerevisiae EC1118. The fermentation kinetics and yeast implantation were monitored using conventional methods and genetic techniques, respectively. The basic chemical parameters of wine were determined using the OIV official methodology, and the fermentative aroma compounds were determined by GC–FID. The results evidenced the limited fermentative power of these yeasts and the differences in their survival after the addition of S. cerevisiae to complete fermentation. Some strains reduced the alcohol and/or increased the total acidity of the wine. The positive effect on sensory wine properties as well as the production of desirable volatile compounds were confirmed for Metschnikowia spp. (Mf278 and Mp176), Lachancea thermotolerans Lt93, and Pichia kluyveri Pkl88. These strains could be used for wine diversification in Galicia. Full article

(This article belongs to the Special Issue Advances in Wine Fermentation)

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14 pages, 2091 KiB

Open AccessArticle

Enhanced Erinacine A Production by Hericium erinaceus Using Solid-State Cultivation

by Po-Yu Cheng, Hung-Yi Liao, Chia-Hung Kuo and Yung-Chuan Liu

Fermentation 2021, 7(3), 182; https://doi.org/10.3390/fermentation7030182 - 5 Sep 2021

Cited by 6 | Viewed by 11483

Abstract

Hericium erinaceus (HE) is a large edible medicinal fungus. Erinacine A (ErA) is a secondary metabolite presented in the mycelia of HE, with pharmacological effects as a nerve growth factor on the central nervous system. In this study, solid-state cultivation of HE was [...] Read more.

Hericium erinaceus (HE) is a large edible medicinal fungus. Erinacine A (ErA) is a secondary metabolite presented in the mycelia of HE, with pharmacological effects as a nerve growth factor on the central nervous system. In this study, solid-state cultivation of HE was carried out in Petri dishes and glass jars for the production of mycelial biomass and ErA. The potato dextrose agar (PDA) had the highest mycelial biomass at an optimal temperature of 25 °C, but no ErA was found in the agar media. In glass jar cultivation, the mycelial biomass and specific yield of ErA in different substrates, particle sizes, substrate weights, nitrogen sources, and inorganic salts were investigated. The ErA was purified by a self-pack silica gel column and a semi-preparative HPLC and was identified by liquid chromatography-tandem mass spectrometer. The best conditions for solid-state cultivation of HE when using corn kernel as substrate, particle size less than 2.38 mm, and addition of 10mM ZnSO₄, 7H₂O, mycelial biomass of 50.24 mg cell dry weight/g substrate was obtained, in addition, the specific yield of ErA could reach 165.36 mg/g cell dry weight. Full article

(This article belongs to the Special Issue Non-dairy Fermented Products)

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17 pages, 4096 KiB

Open AccessArticle

Mechanisms of Metabolic Adaptation in Wine Yeasts: Role of Gln3 Transcription Factor

by Aroa Ferrer-Pinós, Víctor Garrigós, Emilia Matallana and Agustín Aranda

Fermentation 2021, 7(3), 181; https://doi.org/10.3390/fermentation7030181 - 5 Sep 2021

Viewed by 3209

Abstract

Wine strains of Saccharomyces cerevisiae have to adapt their metabolism to the changing conditions during their biotechnological use, from the aerobic growth in sucrose-rich molasses for biomass propagation to the anaerobic fermentation of monosaccharides of grape juice during winemaking. Yeast have molecular [...] Read more.

Wine strains of Saccharomyces cerevisiae have to adapt their metabolism to the changing conditions during their biotechnological use, from the aerobic growth in sucrose-rich molasses for biomass propagation to the anaerobic fermentation of monosaccharides of grape juice during winemaking. Yeast have molecular mechanisms that favor the use of preferred carbon and nitrogen sources to achieve such adaptation. By using specific inhibitors, it was determined that commercial strains offer a wide variety of glucose repression profiles. Transcription factor Gln3 has been involved in glucose and nitrogen repression. Deletion of GLN3 in two commercial wine strains produced different mutant phenotypes and only one of them displayed higher glucose repression and was unable to grow using a respiratory carbon source. Therefore, the role of this transcription factor contributes to the variety of phenotypic behaviors seen in wine strains. This variability is also reflected in the impact of GLN3 deletion in fermentation, although the mutants are always more tolerant to inhibition of the nutrient signaling complex TORC1 by rapamycin, both in laboratory medium and in grape juice fermentation. Therefore, most aspects of nitrogen catabolite repression controlled by TORC1 are conserved in winemaking conditions. Full article

(This article belongs to the Special Issue Yeast Biotechnology 5.0)

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13 pages, 3976 KiB

Open AccessArticle

Optimization of the Nutrient Medium for Flammulina velutipes Submerged Biomass Production and Micromorphology of Its Mycelium

by Larissa Krasnopolskaya, Maria Shuktueva, Aleksandr Golyshkin, Nailya Almyasheva and Maria Yarina

Fermentation 2021, 7(3), 180; https://doi.org/10.3390/fermentation7030180 - 5 Sep 2021

Cited by 3 | Viewed by 3282

Abstract

Based on the assessment of the trophic needs of basidiomycete Flammulina velutipes and the optimization of the composition of the nutrient medium using design of experimental approach, the yield of the submerged biomass of the fungus was increased to 41 g/L, the duration [...] Read more.

Based on the assessment of the trophic needs of basidiomycete Flammulina velutipes and the optimization of the composition of the nutrient medium using design of experimental approach, the yield of the submerged biomass of the fungus was increased to 41 g/L, the duration of the cultivation process was reduced to 5 days. For this purpose, the 2⁴ full factorial design, the Box–Wilson steep ascent method and the construction of the response surface were used. Using the method of scanning electron microscopy, it was shown that the studied F. velutipes strain grew in the form of small spherical pellets with a diameter of 1–2 mm on an optimized medium. The surface of the pellets was loose; the inner part was filled with hyphae tightly adjacent to each other. The center of the pellets had no cavity. F. velutipes pellets were formed by septate hyphae with clamp connections. The micromorphological characteristics of the submerged F. velutipes mycelium ensured a high diffusion of nutrients and oxygen into the pellets and their maximum filling of the volume of the culture medium. Full article

(This article belongs to the Special Issue Biotransformation of Plant Materials by Molds and Higher Fungi)

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12 pages, 1350 KiB

Open AccessArticle

Limosilactobacillus fermentum SWP-AFFS02 Improves the Growth and Survival Rate of White Shrimp via Regulating Immunity and Intestinal Microbiota

by Bao-Hong Lee, Wei-Hsuan Hsu, You-Zuo Chen, Kung-Ting Hsu and Tzu-Ming Pan

Fermentation 2021, 7(3), 179; https://doi.org/10.3390/fermentation7030179 - 4 Sep 2021

Cited by 10 | Viewed by 3659

Abstract

White shrimp Litopenaeus vannamei is an important species of farmed shrimp. Intestinal bacterial composition and immune activity play important roles in regulating the health condition of shrimp. Lactic acid bacteria Limosilactobacillus fermentum SWP-AFFS02 was isolated from the intestine of sea fish Rachycentron canadum [...] Read more.

White shrimp Litopenaeus vannamei is an important species of farmed shrimp. Intestinal bacterial composition and immune activity play important roles in regulating the health condition of shrimp. Lactic acid bacteria Limosilactobacillus fermentum SWP-AFFS02 was isolated from the intestine of sea fish Rachycentron canadum, and the potential of its effect on growth, immunity, and intestinal microbiota of L. vannamei shrimp was investigated. Shrimps received feed with or without the addition of 8 log CFU/g L. fermentum SWP-AFFS02 thrice a day for 8 weeks. After 8-week treatment, weight gain, feed conversion rate, and survival rate of shrimp were greater in the L. fermentum SWP-AFFS02-feed group than in the control group. L. fermentum SWP-AFFS02 treatment increased the number of granular cells and semi-granular cells and decreased hyaline cell number when compared to the control group. L. fermentum SWP-AFFS02 promoted prophenoloxidase (PO) activity through increasing immune-associated gene expression in the hepatopancreas of shrimp. In addition, administration of feed containing L. fermentum SWP-AFFS02 regulated intestinal microbiota via decreasing the ratio of pathogenic bacteria, such as Vibrionaceae and Enterobacteriaceae, in the intestine of shrimp. This study demonstrated that administration of L. fermentum SWP-AFFS02 effectively prevented infection of L. vannamei shrimp by regulating intestinal microbiota and enhancing immunity in shrimp to increase the growth and improve their health status, which acted as a probiotic and provided beneficial effects on shrimp. Full article

(This article belongs to the Section Industrial Fermentation)

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20 pages, 4987 KiB

Open AccessArticle

Nutritionally Enhanced Probioticated Whole Pineapple Juice

by Wilawan Palachum, Wanna Choorit and Yusuf Chisti

Fermentation 2021, 7(3), 178; https://doi.org/10.3390/fermentation7030178 - 4 Sep 2021

Cited by 5 | Viewed by 8562

Abstract

Nutritionally enhanced probioticated whole pineapple juice (WPJ, comprising juice of pineapple pulp and peel) beverages were produced by fermentation of WPJ with the probiotic bacterium Lactobacillus plantarum WU-P19. The 12 h fermented juice contained between 2.1 × 10⁹ and 3.7 × 10 [...] Read more.

Nutritionally enhanced probioticated whole pineapple juice (WPJ, comprising juice of pineapple pulp and peel) beverages were produced by fermentation of WPJ with the probiotic bacterium Lactobacillus plantarum WU-P19. The 12 h fermented juice contained between 2.1 × 10⁹ and 3.7 × 10⁹ live cells of the probiotic per milliliter, depending on the beverage formulation. The beverage had a pH of around 4.1 and a lactic acid content of ~12.8 g L⁻¹. It had a total sugar (glucose, sucrose, fructose, maltose) content of ~100.2 g L⁻¹. During fermentation, some of the initial glucose and fructose were consumed by the probiotic, but sucrose and maltose were not consumed. The original WPJ was free of vitamin B12, but fermentation enhanced vitamin B12 content (~19.5 mg L⁻¹). In addition, fermentation enhanced the concentrations of vitamins B2, B3, and B6, but the bacterium consumed some of the vitamin B1 originally present. From a nutritional perspective, the final probioticated beverage was a good source of vitamin B12, vitamin C and vitamin B6. In addition, it contained nutritionally useful levels of vitamins B1, B2, and B3. The calorific value of the final beverage was 56.94 kcal per 100 mL. The product was stable during 21-day refrigerated (4 °C) storage. Full article

(This article belongs to the Special Issue Food Fermentation for Better Nutrition, Health and Sustainability)

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10 pages, 1184 KiB

Open AccessArticle

Survivability of Collagen-Peptide Microencapsulated Lactic Acid Bacteria during Storage and Simulated Gastrointestinal Conditions

by Sun-Il Kim, Jin-Woo Kim, Ki-Tae Kim and Chang-Ho Kang

Fermentation 2021, 7(3), 177; https://doi.org/10.3390/fermentation7030177 - 3 Sep 2021

Cited by 11 | Viewed by 3728

Abstract

The intracellular homeostasis of lyophilized lactic acid bacteria (LAB) is destroyed by extreme cold stress, resulting in decreased stability. This study aimed to verify the validity of collagen as a potential protective agent for improving microbial stability deteriorated by freezing. The collagen types [...] Read more.

The intracellular homeostasis of lyophilized lactic acid bacteria (LAB) is destroyed by extreme cold stress, resulting in decreased stability. This study aimed to verify the validity of collagen as a potential protective agent for improving microbial stability deteriorated by freezing. The collagen types used in this study were low molecular weight collagen (LC) of less than 1000 Da and low molecular weight collagen-peptide (LCP) of less than 300 Da. By the accelerated stability test according to the addition of each collagen type, a 3% LCP displaying a protective effect on the viability of various LAB strains (Lactoplantibacillus plantarum MG989, Lactococcus lactis MG5125, Enterococcus faecium MG5232, Bifidobacterium animalis ssp. lactis MG741, and Streptococcus thermophilus MG5140) was finally selected. It was evaluated whether LCP enhances bacterial stability, survivability in the gastrointestinal (GI) tract, and heat resistance. LCP significantly improved the viability of all strains in the GI tract compared to sucrose and skim milk, which are conventional protective agents. Based on morphological observations, LCP was uniformly coated on the cell surface, resulting in protective effects against multiple external stress stimuli. Such findings indicate the applicability of LCP as an unprecedented protective agent, which can improve the stability of various probiotics with antifreeze effects. Full article

(This article belongs to the Special Issue Probiotics, Prebiotics, and Their Application in the Production of Functional Foods)

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14 pages, 2665 KiB

Open AccessArticle

Survey of Inoculated Commercial Saccharomyces cerevisiae in Winery-Based Trials

by Filomena L. Duarte and M. Margarida Baleiras-Couto

Fermentation 2021, 7(3), 176; https://doi.org/10.3390/fermentation7030176 - 3 Sep 2021

Cited by 3 | Viewed by 2334

Abstract

Wine production has developed from spontaneous to controlled fermentations using commercial active dry yeasts (ADY). In this study, S. cerevisiae commercial ADY were tested, and yeast community dynamics were monitored at different fermentation stages in three winery-based trials with volumes ranging from 60 [...] Read more.

Wine production has developed from spontaneous to controlled fermentations using commercial active dry yeasts (ADY). In this study, S. cerevisiae commercial ADY were tested, and yeast community dynamics were monitored at different fermentation stages in three winery-based trials with volumes ranging from 60 L to 250 hL. The differentiation of S. cerevisiae strains was achieved using microsatellite markers. In Experiment 1, results showed that both ADY strains revealed similar profiles, despite being described by the producer as having different properties. In Experiment 2, higher genetic diversity was detected when co-inoculation was tested, while in sequential inoculation, the initial ADY seemed to dominate throughout all fermentation. Pilot-scale red wine fermentations were performed in Experiment 3, where one single ADY strain was tested along with different oenological additives. Surprisingly, these trials showed an increase in distinct profiles towards the end of fermentation, indicating that the dominance of the ADY was lower than in the blank modality. The use of ADY is envisaged to promote a controlled and efficient alcoholic fermentation, and their purchase represents an important cost for wineries. Therefore, it is most relevant to survey commercial ADY during wine fermentation to understand if their use is effective. Full article

(This article belongs to the Special Issue Yeast Biotechnology 5.0)

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17 pages, 16584 KiB

Open AccessArticle

Two-Stage Anaerobic Codigestion of Crude Glycerol and Micro-Algal Biomass for Biohydrogen and Methane Production by Anaerobic Sludge Consortium

by Sureewan Sittijunda, Napapat Sitthikitpanya, Pensri Plangklang and Alissara Reungsang

Fermentation 2021, 7(3), 175; https://doi.org/10.3390/fermentation7030175 - 31 Aug 2021

Cited by 18 | Viewed by 2892

Abstract

Optimization of factors affecting biohydrogen production from the codigestion of crude glycerol and microalgal biomass by anaerobic sludge consortium was conducted. The experiments were designed by a response surface methodology with central composite design. The factors affecting the production of hydrogen were the [...] Read more.

Optimization of factors affecting biohydrogen production from the codigestion of crude glycerol and microalgal biomass by anaerobic sludge consortium was conducted. The experiments were designed by a response surface methodology with central composite design. The factors affecting the production of hydrogen were the concentrations of crude glycerol, microalgal biomass, and inoculum. The maximum hydrogen production (655.1 mL-H₂/L) was achieved with 13.83 g/L crude glycerol, 23.1 g-VS/L microalgal biomass, and 10.3% (v/v) inoculum. The hydrogenic effluents obtained under low, high, and optimal conditions were further used as substrates for methane production. Methane production rates and methane yield of 868.7 mL-CH₄/L and 2.95 mL-CH₄/L-h were attained with the effluent produced under optimum conditions. The use of crude glycerol and microalgal biomass as cosubstrates had an antagonistic effect on biohydrogen production and a synergistic effect on methane fermentation. The two-stage process provided a more attractive solution, with a total energy of 1.27 kJ/g-VS_added, than the one-stage process. Full article

(This article belongs to the Special Issue Biomass and Waste Valorization)

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20 pages, 7495 KiB

Open AccessEditor’s ChoiceArticle

Mixed-Culture Metagenomics of the Microbes Making Sour Beer

by Renan Eugênio Araujo Piraine, Fábio Pereira Leivas Leite and Matthew L. Bochman

Fermentation 2021, 7(3), 174; https://doi.org/10.3390/fermentation7030174 - 30 Aug 2021

Cited by 9 | Viewed by 4792

Abstract

Mixed microbial cultures create sour beers but many brewers do not know which microbes comprise their cultures. The objective of this work was to use deep sequencing to identify microorganisms in sour beers brewed by spontaneous and non-spontaneous methods. Twenty samples were received [...] Read more.

Mixed microbial cultures create sour beers but many brewers do not know which microbes comprise their cultures. The objective of this work was to use deep sequencing to identify microorganisms in sour beers brewed by spontaneous and non-spontaneous methods. Twenty samples were received from brewers, which were processed for microbiome analysis by next generation sequencing. For bacteria, primers were used to amplify the V3-V4 region of the 16S rRNA gene; fungal DNA detection was performed using primers to amplify the entire internal transcribed spacer region. The sequencing results were then used for taxonomy assignment, sample composition, and diversity analyses, as well as nucleotide BLAST searching. We identified 60 genera and 140 species of bacteria, of which the most prevalent were Lactobacillus acetotolerans, Pediococcus damnosus, and Ralstonia picketti/mannitolilytica. In fungal identification, 19 genera and 26 species were found, among which the most common yeasts were Brettanomyces bruxellensis and Saccharomyces cerevisiae. In some cases, genetic material from more than 60 microorganisms was found in a single sample. In conclusion, we were able to determine the microbiomes of various mixed cultures used to produce beer, providing useful information to better understand the sour beer fermentation process and brewing techniques. Full article

(This article belongs to the Special Issue Mixed Culture Fermentation)

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12 pages, 1505 KiB

Open AccessArticle

The Use of Life Cycle Assessment in the Support of the Development of Fungal Food Products from Surplus Bread

by Pedro Brancoli, Rebecca Gmoser, Mohammad J. Taherzadeh and Kim Bolton

Fermentation 2021, 7(3), 173; https://doi.org/10.3390/fermentation7030173 - 30 Aug 2021

Cited by 17 | Viewed by 4098

Abstract

The use of food waste as feedstock in the manufacture of high-value products is a promising avenue to contribute to circular economy. Considering that the majority of environmental impacts of products are determined in the early phases of product development, it is crucial [...] Read more.

The use of food waste as feedstock in the manufacture of high-value products is a promising avenue to contribute to circular economy. Considering that the majority of environmental impacts of products are determined in the early phases of product development, it is crucial to integrate life cycle assessment during these phases. This study integrates environmental considerations in the development of solid-state fermentation based on the cultivation of N. intermedia for the production of a fungal food product using surplus bread as a substrate. The product can be sold as a ready-to-eat meal to reduce waste while generating additional income. Four inoculation scenarios were proposed, based on the use of bread, molasses, and glucose as substrate, and one scenario based on backslopping. The environmental performance was assessed, and the quality of the fungal product was evaluated in terms of morphology and protein content. The protein content of the fungal food product was similar in all scenarios, varying from 25% to 29%. The scenario based on backslopping showed the lowest environmental impacts while maintaining high protein content. The results show that the inoculum production and the solid-state fermentation are the two environmental hotspots and should be in focus when optimizing the process. Full article

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

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8 pages, 250 KiB

Open AccessArticle

Addition of Active Dry Yeast Could Enhance Feed Intake and Rumen Bacterial Population While Reducing Protozoa and Methanogen Population in Beef Cattle

by Kampanat Phesatcha, Krittika Chunwijitra, Burarat Phesatcha, Metha Wanapat and Anusorn Cherdthong

Fermentation 2021, 7(3), 172; https://doi.org/10.3390/fermentation7030172 - 30 Aug 2021

Cited by 9 | Viewed by 3482

Abstract

Urea–lime-treated rice straw fed to Thai native beef cattle was supplemented with dry yeast (DY) (Saccharomyces cerevisiae) to assess total feed intake, nutrient digestibility, rumen microorganisms, and methane (CH₄) production. Sixteen Thai native beef cattle at 115 ± 10 [...] Read more.

Urea–lime-treated rice straw fed to Thai native beef cattle was supplemented with dry yeast (DY) (Saccharomyces cerevisiae) to assess total feed intake, nutrient digestibility, rumen microorganisms, and methane (CH₄) production. Sixteen Thai native beef cattle at 115 ± 10 kg live weight were divided into four groups that received DY supplementation at 0, 1, 2, and 3 g/hd/d using a randomized completely block design. All animals were fed concentrate mixture at 0.5% of body weight, with urea–lime-treated rice straw fed ad libitum. Supplementation with DY enhanced total feed intake and digestibility of neutral detergent fiber and acid detergent fiber (p < 0.05), but dry matter, organic matter and crude protein were similar among treatments (p > 0.05). Total volatile fatty acid (VFA) and propionic acid (C3) increased (p < 0.05) with 3 g/hd/d DY supplementation, while acetic acid (C2) and butyric acid (C4) decreased. Protozoal population and CH₄ production in the rumen decreased as DY increased (p < 0.05). Populations of F. succinogenes and R. flavefaciens increased (p < 0.05), whereas methanogen population decreased with DY addition at 3 g/hd/d, while R. albus was stable (p > 0.05) throughout the treatments. Thus, addition of DY to cattle feed increased feed intake, rumen fermentation, and cellulolytic bacterial populations. Full article

(This article belongs to the Special Issue Yeast Biotechnology 5.0)

23 pages, 956 KiB

Open AccessReview

Commercially Available Non-Saccharomyces Yeasts for Winemaking: Current Market, Advantages over Saccharomyces, Biocompatibility, and Safety

by Ricardo Vejarano and Angie Gil-Calderón

Fermentation 2021, 7(3), 171; https://doi.org/10.3390/fermentation7030171 - 28 Aug 2021

Cited by 55 | Viewed by 8050

Abstract

About 42 commercial products based on non-Saccharomyces yeasts are estimated as available on the market, being mostly pure cultures (79%), with a predominance of Torulaspora delbrueckii, Lachancea thermotolerans, and Metschnikowia pulcherrima. The others are multi-starter consortia that include non-Saccharomyces [...] Read more.

About 42 commercial products based on non-Saccharomyces yeasts are estimated as available on the market, being mostly pure cultures (79%), with a predominance of Torulaspora delbrueckii, Lachancea thermotolerans, and Metschnikowia pulcherrima. The others are multi-starter consortia that include non-Saccharomyces/Saccharomyces mixtures or only non-Saccharomyces species. Several commercial yeasts have shown adequate biocompatibility with S. cerevisiae in mixed fermentations, allowing an increased contribution of metabolites of oenological interest, such as glycerol, esters, higher alcohols, acids, thiols, and terpenes, among others, in addition to a lower production of acetic acid, volatile phenols, biogenic amines, or urea. Multi-starter inoculations are also reviewed here, which show adequate biocompatibility and synergy between species. In certain cases, the aromatic profile of wines based on grape varieties considered neutral is improved. In addition, several yeasts show the capacity as biocontrollers against contaminating microorganisms. The studies conducted to date demonstrate the potential of these yeasts to improve the properties of wine as an alternative and complement to the traditional S. cerevisiae. Full article

(This article belongs to the Special Issue Enological Repercussions of Non-Saccharomyces Species 3.0)

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14 pages, 716 KiB

Open AccessArticle

Development of an Araucaria araucana Beer-like Beverage: Process and Product

by Angélica Durán, José Reyes-De-Corcuera, Gustavo Garay, Pedro Valencia and Alejandra Urtubia

Fermentation 2021, 7(3), 170; https://doi.org/10.3390/fermentation7030170 - 28 Aug 2021

Cited by 3 | Viewed by 2788

Abstract

The seed from the Araucaria araucana (in Spanish, piñon) tree, native to Chile and Argentina, is sold mainly as raw seed. Engineering a process to add value to piñon has the potential to positively impact local indigenous communities with very little ecological impact [...] Read more.

The seed from the Araucaria araucana (in Spanish, piñon) tree, native to Chile and Argentina, is sold mainly as raw seed. Engineering a process to add value to piñon has the potential to positively impact local indigenous communities with very little ecological impact because it is routinely harvested in the wild. This study evaluated the feasibility of using 100% piñon, or as a blend with barley malt, to produce a beer-like beverage, while also evaluating consumer acceptance of the beverage’s piñon characteristics. Prototypes generated based on 93% piñon and 7% oat (enzymatic treatment of α-amylase, glucoamylase, protease and β-glucanase), as well as 50% piñon and 50% barley (no external enzymatic treatment), were evaluated. Overall acceptability by a consumer acceptance panel (21 consumers) rated the 100% piñon and the piñon–barley malt blend 5/9 and 7/9, respectively. The piñon–barley malt blend prototype stood out for its low level of carbohydrates, high potassium content and banana and clove aromas. Full article

(This article belongs to the Special Issue Advances in Beverages, Food, Yeast and Brewing Research)

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