Fermentation

20 pages, 3826 KiB

Open AccessArticle

Single and Multiple Inoculum of Lactiplantibacillus plantarum Strains in Table Olive Lab-Scale Fermentations

by Barbara Lanza, Miriam Zago, Sara Di Marco, Giuseppina Di Loreto, Martina Cellini, Flavio Tidona, Barbara Bonvini, Martina Bacceli and Nicola Simone

Fermentation 2020, 6(4), 126; https://doi.org/10.3390/fermentation6040126 - 18 Dec 2020

Cited by 10 | Viewed by 3687

Abstract

In order to improve the olives’ quality, and to reduce the de-bittering time during the table olive fermentation process, it is necessary to pilot the fermentation by inoculating the brine with selected cultures of microorganisms. Some probiotic tests, such as resistance/sensitivity to antibiotics, [...] Read more.

In order to improve the olives’ quality, and to reduce the de-bittering time during the table olive fermentation process, it is necessary to pilot the fermentation by inoculating the brine with selected cultures of microorganisms. Some probiotic tests, such as resistance/sensitivity to antibiotics, bile salt hydrolase (BSH) activity, growth at acidic pH, an auto-aggregation assay, and a test of the production of exopolysaccharides, were carried out in order to screen 35 oleuropeinolytic Lactiplantibacillus plantarum subsp. plantarum strains to be used in guided fermentations of table olives. On the basis of the technological and probiotic screening, we analyzed the progress of three different lab-scale fermentations of Olea europaea L. Itrana cv. olives inoculated with spontaneous, single, and multiple starters: jar A was left to ferment spontaneously; jar B was inoculated with a strongly oleuropeinolytic strain (L. plantarum B1); jar C was inoculated with a multiple inoculum (L. plantarum B1 + L. plantarum B51 + L. plantarum B124). The following parameters were monitored during the fermentation: pH, titratable acidity, NaCl concentration, the degradation of bio-phenols, and the enrichment rate of hydroxytyrosol and tyrosol in the olive’s flesh, oil and brine. The degradation of secoiridoid glucosides appeared to be faster in the inoculated jars than in the spontaneously-fermented jar. The production of hydroxytyrosol and ligstroside aglycons was high. This indicated a complete degradation of the oleuropein and a partial degradation of the ligstroside. The multiple inoculum ensured a complete debittering, and could give probiotic traits. The presence of L. plantarum B1 and B124 as a fermentation starter guarantees an optimal trend of de-bittering and fermentation variables, thus ensuring the production of a better final product. L. plantarum B51 could be considered to be a promising probiotic candidate for obtaining probiotic food of completely vegetable origin. Full article

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

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25 pages, 3262 KiB

Open AccessArticle

Observations on the Malting of Ancient Wheats: Einkorn, Emmer and Spelt

by Alice Fujita, Senay Simsek and Paul B. Schwarz

Fermentation 2020, 6(4), 125; https://doi.org/10.3390/fermentation6040125 - 14 Dec 2020

Cited by 6 | Viewed by 4117

Abstract

There have been tremendous marketing efforts and consumer interest in the so-called ancient grains. Einkorn, emmer and spelt, which are sometimes referred to as ancient wheats, are frequently included in this category, and have gained some attention among brewers. The objective of the [...] Read more.

There have been tremendous marketing efforts and consumer interest in the so-called ancient grains. Einkorn, emmer and spelt, which are sometimes referred to as ancient wheats, are frequently included in this category, and have gained some attention among brewers. The objective of the current study was to compare the malting behavior and quality of einkorn, emmer and spelt cultivars obtained from the same growing environment. Aside from standard malt quality traits, the levels of β-amylase, protease, xylanase, wort arabinoxylans and wort phenolic acids were measured. While protein levels of the samples were higher (11.4–14.0%) than normally selected for wheat malt, the results indicated that malts of acceptable quality in terms of extract and amylolytic activity can be prepared from the three grain types. However, the ideal malting protocol will likely differ between the grains. The kernels of einkorn are significantly smaller, and steep hydration and malt modification are quicker. In terms of potential health benefits from antioxidant capacity and dietary fiber, wort from einkorn trended to higher levels of free and conjugated ferulic acid, as well as high-molecular-weight arabinoxylan. Full article

(This article belongs to the Special Issue Brewing & Distilling 2.0)

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19 pages, 334 KiB

Open AccessReview

Kluyveromyces marxianus: Current State of Omics Studies, Strain Improvement Strategy and Potential Industrial Implementation

by Dung Minh Ha-Tran, Trinh Thi My Nguyen and Chieh-Chen Huang

Fermentation 2020, 6(4), 124; https://doi.org/10.3390/fermentation6040124 - 11 Dec 2020

Cited by 17 | Viewed by 5143

Abstract

Bioethanol is considered an excellent alternative to fossil fuels, since it importantly contributes to the reduced consumption of crude oil, and to the alleviation of environmental pollution. Up to now, the baker yeast Saccharomyces cerevisiae is the most common eukaryotic microorganism used in [...] Read more.

Bioethanol is considered an excellent alternative to fossil fuels, since it importantly contributes to the reduced consumption of crude oil, and to the alleviation of environmental pollution. Up to now, the baker yeast Saccharomyces cerevisiae is the most common eukaryotic microorganism used in ethanol production. The inability of S. cerevisiae to grow on pentoses, however, hinders its effective growth on plant biomass hydrolysates, which contain large amounts of C₅ and C₁₂ sugars. The industrial-scale bioprocessing requires high temperature bioreactors, diverse carbon sources, and the high titer production of volatile compounds. These criteria indicate that the search for alternative microbes possessing useful traits that meet the required standards of bioethanol production is necessary. Compared to other yeasts, Kluyveromyces marxianus has several advantages over others, e.g., it could grow on a broad spectrum of substrates (C₅, C₆ and C₁₂ sugars); tolerate high temperature, toxins, and a wide range of pH values; and produce volatile short-chain ester. K. marxianus also shows a high ethanol production rate at high temperature and is a Crabtree-negative species. These attributes make K. marxianus promising as an industrial host for the biosynthesis of biofuels and other valuable chemicals. Full article

(This article belongs to the Special Issue Ethanol and Value-Added Co-Products 2.0)

23 pages, 1030 KiB

Open AccessReview

Brewer’s Spent Yeast (BSY), an Underutilized Brewing By-Product

by Alice Jaeger, Elke K. Arendt, Emanuele Zannini and Aylin W. Sahin

Fermentation 2020, 6(4), 123; https://doi.org/10.3390/fermentation6040123 - 11 Dec 2020

Cited by 65 | Viewed by 20320

Abstract

The repurposing of by-products and the reduction of waste from food processing streams is an ever-increasing area of interest. Brewer’s spent yeast (BSY) is a prevalent by-product of the brewing industry. The spent yeast cells are removed at the end of the bulk [...] Read more.

The repurposing of by-products and the reduction of waste from food processing streams is an ever-increasing area of interest. Brewer’s spent yeast (BSY) is a prevalent by-product of the brewing industry. The spent yeast cells are removed at the end of the bulk fermentation. A small amount of it is used to start the next batch of fermentation; however, the majority of the spent yeast is discarded. This discarded yeast is high in nutrients, in particular proteins, vitamins and minerals, as well as containing functional and biologically active compounds such as polyphenols, antioxidants, β-glucans and mannoproteins. At present, BSY is mainly used in animal feed as a cheap and readily available source of protein. This review explores alternative, value-added applications for brewer’s spent yeast including nutritional ingredients, functional food additives as well as non-food applications. A major challenge in the utilization of BSY in food for human consumption is the high level of RNA. An excess of RNA in the diet can lead to an increase in uric acid in the bloodstream, potentially causing painful health conditions like gout. This issue can be overcome by RNA degradation and removal via additional treatment, namely heat treatment and enzymatic treatment. There is potential for the use of BSY ingredients in various food applications, including meat substitutes, bakery products and savory snacks. Full article

(This article belongs to the Special Issue Brewing & Distilling 2.0)

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10 pages, 2068 KiB

Open AccessArticle

Exploring the Impact of Lipid-Rich Food Industry Waste Carbon Sources on the Growth of Candida cylindracea DSM 2031

by Bartłomiej Zieniuk, Patrycja Mazurczak-Zieniuk and Agata Fabiszewska

Fermentation 2020, 6(4), 122; https://doi.org/10.3390/fermentation6040122 - 11 Dec 2020

Cited by 7 | Viewed by 2691

Abstract

The aim of this study was to evaluate the possibility of using several lipid-rich food industry wastes in the culture medium on the growth of Candida cylindracea DSM 2031 yeast strain. Four lipid wastes from the food industry: waste fish oil, rancid ghee, [...] Read more.

The aim of this study was to evaluate the possibility of using several lipid-rich food industry wastes in the culture medium on the growth of Candida cylindracea DSM 2031 yeast strain. Four lipid wastes from the food industry: waste fish oil, rancid ghee, waste pork lard, and waste duck processing oil were investigated. It has been shown in the laboratory scale that the above-mentioned wastes can be used to obtain biomass and produce lipolytic enzymes by the tested strain and the C. cylindracea extracellular lipase is not constitutive. High yields of biomass (12.84, 12.75, and 12.24 g/dm³) were obtained in media containing waste duck processing oil, olive oil, and waste pork lard, respectively. The highest lipolytic activity was obtained in the media containing waste fish oil and rancid ghee (0.050 and 0.047 U/cm³). During 192-h flask cultures the highest extracellular lipase activity and biomass yield were observed in the late logarithmic phase. The study showed that there is a potential for waste management to produce lipolytic enzymes or to produce yeast biomass. The use of waste substrates may contribute to lowering the costs of commercial production, and such a solution is part of the sustainable development strategy. Full article

(This article belongs to the Special Issue Yeast Biotechnology 4.0)

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24 pages, 1604 KiB

Open AccessReview

Inclusion of Probiotics into Fermented Buffalo (Bubalus bubalis) Milk: An Overview of Challenges and Opportunities

by A.M.N.L. Abesinghe, Hasitha Priyashantha, P.H.P. Prasanna, Maheshika S. Kurukulasuriya, C.S. Ranadheera and J.K. Vidanarachchi

Fermentation 2020, 6(4), 121; https://doi.org/10.3390/fermentation6040121 - 10 Dec 2020

Cited by 24 | Viewed by 8198

Abstract

Buffalo-milk-based dairy products provide various health benefits to humans since buffalo milk serves as a rich source of protein, fat, lactose, calcium, iron, phosphorus, vitamin A and natural antioxidants. Dairy products such as Meekiri, Dadih, Dadi and Lassie, which are derived from Artisanal [...] Read more.

Buffalo-milk-based dairy products provide various health benefits to humans since buffalo milk serves as a rich source of protein, fat, lactose, calcium, iron, phosphorus, vitamin A and natural antioxidants. Dairy products such as Meekiri, Dadih, Dadi and Lassie, which are derived from Artisanal fermentation of buffalo milk, have been consumed for many years. Probiotic potentials of indigenous microflora in fermented buffalo milk have been well documented. Incorporation of certain probiotics into the buffalo-milk-based dairy products conferred vital health benefits to the consumers, although is not a common practice. However, several challenges are associated with incorporating probiotics into buffalo-milk-based dairy products. The viability of probiotic bacteria can be reduced due to processing and environmental stress during storage. Further, incompatibility of probiotics with traditional starter cultures and high acidity of fermented dairy products may lead to poor viability of probiotics. The weak acidifying performance of probiotics may affect the organoleptic quality of fermented dairy products. Besides these challenges, several innovative technologies such as the use of microencapsulated probiotics, ultrasonication, the inclusion of prebiotics, use of appropriate packaging and optimal storage conditions have been reported, promising stability and viability of probiotics in buffalo-milk-based fermented dairy products. Full article

(This article belongs to the Special Issue Probiotic Delivery through Non-Bovine Milk and Milk Products: Trends, Novelties and Benefits)

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15 pages, 1847 KiB

Open AccessReview

Fermentation as an Alternative Process for the Development of Bioinsecticides

by Alejandra B. Omarini, Fernanda Achimón, Vanessa D. Brito and Julio A. Zygadlo

Fermentation 2020, 6(4), 120; https://doi.org/10.3390/fermentation6040120 - 08 Dec 2020

Cited by 3 | Viewed by 7060

Abstract

Currently, insect pest control is carried out through the application of synthetic insecticides which have been related to harmful effects on both human and environmental health, as well as to the development of resistant pest populations. In this context, the development of new [...] Read more.

Currently, insect pest control is carried out through the application of synthetic insecticides which have been related to harmful effects on both human and environmental health, as well as to the development of resistant pest populations. In this context, the development of new and natural insecticides is necessary. Agricultural and forestry waste or by-products are very low-cost substrates that can be converted by microorganisms into useful value-added bioactive products through fermentation processes. In this review we discuss recent discoveries of compounds obtained from fermented substrates along with their insecticidal, antifeedant, and repellent activities. Fermentation products obtained from agricultural and forestry waste are described in detail. The fermentation of the pure secondary metabolite such as terpenes and phenols is also included. Full article

(This article belongs to the Special Issue Biomass Conversion: Fermentation Chemicals and Fuels)

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10 pages, 458 KiB

Open AccessArticle

Assessment of Microbiological Quality and Physicochemical Parameters of Fruhe Made by Ovine and Goat Milk: A Sardinian (Italy) Cheese

by Marco A. Murgia, Pietrino Deiana, Anna Nudda, Fabio Correddu, Luigi Montanari and Nicoletta P. Mangia

Fermentation 2020, 6(4), 119; https://doi.org/10.3390/fermentation6040119 - 05 Dec 2020

Cited by 8 | Viewed by 2858

Abstract

Fruhe (Casu axedu) is a fresh cheese, traditionally manufactured in Sardinia (Italy) from sheep or goat milk, characterized by a compact coagulum obtained from raw or heat-treated whole milk. The objective of this study was to investigate the microbiological quality and physicochemical parameters [...] Read more.

Fruhe (Casu axedu) is a fresh cheese, traditionally manufactured in Sardinia (Italy) from sheep or goat milk, characterized by a compact coagulum obtained from raw or heat-treated whole milk. The objective of this study was to investigate the microbiological quality and physicochemical parameters of the sheep and goat Fruhe types of cheese at 21 days of cold storage. Chemical analyses showed that all Fruhe cheese samples were characterized by a pH below 4.4 and a variable content of total solid (22.75–21.06 g/100 g) proteins (5.4–10 g/100 g) and fat (3.9–15.7 g/100 g). The average residual lactose content was 2.6 g/100 g, while lactic acid content was 1.8 g/100 g. Microbial analyses revealed a high number of Lactic Acid Bacteria for both thermophilic and mesophilic streptococci (9 log CFU/g), and no pathogenic bacteria were found. The content of Free Amino Acids and Free Fatty acids point out that a good activity of rennet and microbial enzymes occurred, although Fruhe cheese is not subject to a ripening process. The present research reports the microbiological and nutritional characteristics of the sheep and goat Fruhe cheese that could represent the basis for further investigations, needful to improve its nutritional quality and to preserve its peculiarities. Full article

(This article belongs to the Special Issue Lactic Acid Fermentation and the Colours of Biotechnology 2.0)

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10 pages, 4470 KiB

Open AccessArticle

Effects of Fermented Kefir as a Functional Feed Additive in Litopenaeus vannamei Farming

by Woosik Choi, Chi-Won Choi, Dang-Bao Son, Byeong-Chul Jeong, Hee-Chang Kim, Hanki Lee and Joo-Won Suh

Fermentation 2020, 6(4), 118; https://doi.org/10.3390/fermentation6040118 - 27 Nov 2020

Cited by 6 | Viewed by 3573

Abstract

Litopenaeus vannamei, known as whiteleg shrimp, is susceptible to infection by pathogenic microorganisms such as viruses and bacteria. Therefore, the prevention of infections in this shrimp is important to regulate the outbreaks of pathogenic microorganisms. In this study, we investigated the effects [...] Read more.

Litopenaeus vannamei, known as whiteleg shrimp, is susceptible to infection by pathogenic microorganisms such as viruses and bacteria. Therefore, the prevention of infections in this shrimp is important to regulate the outbreaks of pathogenic microorganisms. In this study, we investigated the effects of kefir as a functional feed additive on innate immunity, survival against WSSV (White Spot Syndrome Virus) and productivity of L. vannamei. As a result, the treatment of kefir could upregulate six of seven genes crucial for innate immunity of L. vannamei. Also, the treatment of kefir directly improved the survival rate of L. vannamei against WSSV infection. Finally, in order to determine whether kefir can improve the productivity of shrimp, we carried out field tests in three aquaculture farms in South Korea. The weight of shrimp fed kefir was increased by 120% as well as the length, compared with that of the control group. These results demonstrate that kefir can be utilized as a functional feed additive to improve both innate immunity and productivity of L. vannamei in shrimp farming with no use of antibiotics. Full article

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

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26 pages, 1332 KiB

Open AccessReview

Rootlets, a Malting By-Product with Great Potential

by Emma Neylon, Elke K. Arendt, Kieran M. Lynch, Emanuele Zannini, Paolo Bazzoli, Thomas Monin and Aylin W. Sahin

Fermentation 2020, 6(4), 117; https://doi.org/10.3390/fermentation6040117 - 26 Nov 2020

Cited by 19 | Viewed by 9733

Abstract

Barley rootlets are the most abundant by-product from the malting industry. Due to the inherent association of the malting industry with brewing and distilling industries, it is also considered a by-product of these industries. Barley rootlets are produced during the germination step of [...] Read more.

Barley rootlets are the most abundant by-product from the malting industry. Due to the inherent association of the malting industry with brewing and distilling industries, it is also considered a by-product of these industries. Barley rootlets are produced during the germination step of malting. These rootlets are a valuable source of nutrition, with protein and fibre holding a large proportion of their composition. Barley rootlets are generally pelletised and used as animal fodder; however, their usage may not be limited to this. Efforts have been made to utilise barley rootlets as food ingredients, sources of enzymes, antioxidants, raw materials in fermentations, and in biochar production. Conversion of this by-product into other/new applications would reduce waste production from their industry origin and reduce some of the impending environmental concerns associated with by-product production. The current review focuses on providing information on the formation, production, and processing of barley rootlets, while also highlighting the composition, quality, and potential applications of barley rootlets. Full article

(This article belongs to the Special Issue Brewing & Distilling 2.0)

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16 pages, 1218 KiB

Open AccessReview

Novel Non-Cerevisiae Saccharomyces Yeast Species Used in Beer and Alcoholic Beverage Fermentations

by James Bruner and Glen Fox

Fermentation 2020, 6(4), 116; https://doi.org/10.3390/fermentation6040116 - 24 Nov 2020

Cited by 13 | Viewed by 7869

Abstract

A great deal of research in the alcoholic beverage industry was done on non-Saccharomyces yeast strains in recent years. The increase in research interest could be attributed to the changing of consumer tastes and the search for new beer sensory experiences, as [...] Read more.

A great deal of research in the alcoholic beverage industry was done on non-Saccharomyces yeast strains in recent years. The increase in research interest could be attributed to the changing of consumer tastes and the search for new beer sensory experiences, as well as the rise in popularity of mixed-fermentation beers. The search for unique flavors and aromas, such as the higher alcohols and esters, polyfunctional thiols, lactones and furanones, and terpenoids that produce fruity and floral notes led to the use of non-cerevisiae Saccharomyces species in the fermentation process. Additionally, a desire to invoke new technologies and techniques for making alcoholic beverages also led to the use of new and novel yeast species. Among them, one of the most widely used non-cerevisiae strains is S. pastorianus, which was used in the production of lager beer for centuries. The goal of this review is to focus on some of the more distinct species, such as those species of Saccharomyces sensu stricto yeasts: S. kudriavzevii, S. paradoxus, S. mikatae, S. uvarum, and S. bayanus. In addition, this review discusses other Saccharomyces spp. that were used in alcoholic fermentation. Most importantly, the factors professional brewers might consider when selecting a strain of yeast for fermentation, are reviewed herein. The factors include the metabolism and fermentation potential of carbon sources, attenuation, flavor profile of fermented beverage, flocculation, optimal temperature range of fermentation, and commercial availability of each species. While there is a great deal of research regarding the use of some of these species on a laboratory scale wine fermentation, much work remains for their commercial use and efficacy for the production of beer. Full article

(This article belongs to the Special Issue Brewing & Distilling 2.0)

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21 pages, 3068 KiB

Open AccessReview

Lactic Acid Bacterial Production of Exopolysaccharides from Fruit and Vegetables and Associated Benefits

by Marie Guérin, Christine Robert-Da Silva, Cyrielle Garcia and Fabienne Remize

Fermentation 2020, 6(4), 115; https://doi.org/10.3390/fermentation6040115 - 21 Nov 2020

Cited by 38 | Viewed by 6809

Abstract

Microbial polysaccharides have interesting and attractive characteristics for the food industry, especially when produced by food grade bacteria. Polysaccharides produced by lactic acid bacteria (LAB) during fermentation are extracellular macromolecules of either homo or hetero polysaccharidic nature, and can be classified according to [...] Read more.

Microbial polysaccharides have interesting and attractive characteristics for the food industry, especially when produced by food grade bacteria. Polysaccharides produced by lactic acid bacteria (LAB) during fermentation are extracellular macromolecules of either homo or hetero polysaccharidic nature, and can be classified according to their chemical composition and structure. The most prominent exopolysaccharide (EPS) producing lactic acid bacteria are Lactobacillus, Leuconostoc, Weissella, Lactococcus, Streptococcus, Pediococcus and Bifidobacterium sp. The EPS biosynthesis and regulation pathways are under the dependence of numerous factors as producing-species or strain, nutrient availability, and environmental conditions, resulting in varied carbohydrate compositions and beneficial properties. The interest is growing for fruits and vegetables fermented products, as new functional foods, and the present review is focused on exploring the EPS that could derive from lactic fermented fruit and vegetables. The chemical composition, biosynthetic pathways of EPS and their regulation mode is reported. The consequences of EPS on food quality, especially texture, are explored in relation to producing species. Attention is given to the scientific investigations on health benefits attributed to EPS such as prebiotic, antioxidant, anti-inflammatory and cholesterol lowering activities. Full article

(This article belongs to the Special Issue Lactic Acid Fermentation and the Colours of Biotechnology 2.0)

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7 pages, 924 KiB

Open AccessCommunication

A New Approach to Producing High Yields of Pulcherrimin from Metschnikowia Yeasts

by Ewelina Pawlikowska, Beata Kolesińska, Maria Nowacka and Dorota Kregiel

Fermentation 2020, 6(4), 114; https://doi.org/10.3390/fermentation6040114 - 21 Nov 2020

Cited by 10 | Viewed by 3703

Abstract

Pulcherrimin, a red iron chelate, is produced by some yeasts and bacteria. It plays important ecological roles in many ecosystems, including growth control, biofilm inhibition and photoprotection. In this study, fifteen yeast strains of the genus Metschnikowia were characterized based on their production [...] Read more.

Pulcherrimin, a red iron chelate, is produced by some yeasts and bacteria. It plays important ecological roles in many ecosystems, including growth control, biofilm inhibition and photoprotection. In this study, fifteen yeast strains of the genus Metschnikowia were characterized based on their production of pulcherrimin. Yeast pulcherrimin was isolated and its purity assessed using ¹H nuclear magnetic resonance spectroscopy. Under experimental conditions, pulcherrimin formation varied depending on both the tested strains and culture media. The best producers formed up to 240 mg/L of pulcherrimin in minimal medium with glucose as the carbon source, supplemented with 0.05% FeCl₃ and 0.1% Tween 80. This study presents a new approach to producing high yields of pulcherrimin from yeasts. Full article

(This article belongs to the Special Issue Fermentation and Bioactive Metabolites 2.0)

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22 pages, 1894 KiB

Open AccessReview

Wine and Non-Dairy Fermented Beverages: A Novel Source of Pro- and Prebiotics

by Alice Vilela, Fernanda Cosme and António Inês

Fermentation 2020, 6(4), 113; https://doi.org/10.3390/fermentation6040113 - 20 Nov 2020

Cited by 15 | Viewed by 7758

Abstract

Probiotics and prebiotics are microbiota-management instruments for improving human health once they may be beneficial for maintaining a healthy community of gut microbiota and bowel function. Probiotic’s main target is the gut, via the gastrointestinal tract, although direct application to other body zones [...] Read more.

Probiotics and prebiotics are microbiota-management instruments for improving human health once they may be beneficial for maintaining a healthy community of gut microbiota and bowel function. Probiotic’s main target is the gut, via the gastrointestinal tract, although direct application to other body zones such as the vaginal tract, the oral cavity, and skin have been studied. The major source of probiotics is fermented dairy products, however, currently, there is a need for novel and non-dairy probiotics, due to the increasing number of lactose-intolerant persons in the world population, tied with the adverse effect of cholesterol contained in fermented dairy foods as well as the increasing number of strict vegetarians. In this review, we describe gut-derived effects in humans of possible microorganisms isolated from wine, such as Saccharomyces and non-Saccharomyces yeasts and bacteria, and other non-dairy fermented beverages. Those microorganisms can be grown and consumed as recommended probiotics, moreover, wine, and other beverages may also be a source of prebiotics such as polyphenols. Full article

(This article belongs to the Special Issue Fermented Foods and Gut Microbiome)

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12 pages, 264 KiB

Open AccessArticle

Effects of Medium Components on Isocitric Acid Production by Yarrowia lipolytica Yeast

by Svetlana V. Kamzolova, Vladimir A. Samoilenko, Julia N. Lunina and Igor G. Morgunov

Fermentation 2020, 6(4), 112; https://doi.org/10.3390/fermentation6040112 - 20 Nov 2020

Cited by 9 | Viewed by 2360

Abstract

The microbiological production of isocitric acid (ICA) is more preferable for its application in medicine and food, because the resulting product contains only the natural isomer—threo-D_S. The aim of the present work was to study ICA production by yeast using sunflower [...] Read more.

The microbiological production of isocitric acid (ICA) is more preferable for its application in medicine and food, because the resulting product contains only the natural isomer—threo-D_S. The aim of the present work was to study ICA production by yeast using sunflower oil as carbon source. 30 taxonomically different yeast strains were assessed for their capability for ICA production, and Y. lipolytica VKM Y-2373 was selected as a promising producer. It was found that ICA production required: the limitation of Y. lipolytica growth by nitrogen, phosphorus, sulfur or magnesium, and an addition of iron, activating aconitate hydratase, a key enzyme of isocitrate synthesis. Another regulatory approach capable to shift acid formation to a predominant ICA synthesis is the use of inhibitors (itaconic and oxalic acids), which blocks the conversion of isocitrate at the level of isocitrate lyase. It is recommended to cultivate Y. lipolytica VKM Y-2373 under nitrogen deficiency conditions with addition of 1.5 mg/L iron and 30 mM itaconic acid. Such optimized nutrition medium provides 70.6 g/L ICA with a ratio between ICA and citric acid (CA) equal 4:1, a mass yield (Y_ICA) of 1.25 g/g and volume productivity (Q_ICA) of 1.19 g/L·h. Full article

(This article belongs to the Special Issue Yeast Biotechnology 4.0)

18 pages, 2856 KiB

Open AccessArticle

Medicinal Chemistry Friendliness of Pigments from Monascus-Fermented Rice and the Molecular Docking Analysis of Their Anti-Hyperlipidemia Properties

by Nina Sun, Dominic Agyei and Dawei Ji

Fermentation 2020, 6(4), 111; https://doi.org/10.3390/fermentation6040111 - 19 Nov 2020

Cited by 6 | Viewed by 2718

Abstract

In this study, the physicochemical properties, pharmacokinetics properties, and drug-likeness of pigments from Monascus-fermented rice (Monascus pigments, MPs) were predicted in silico using SwissADME tool. In silico prediction of physicochemical properties showed that MPs had desirable lipophilic drug-like physicochemical properties including [...] Read more.

In this study, the physicochemical properties, pharmacokinetics properties, and drug-likeness of pigments from Monascus-fermented rice (Monascus pigments, MPs) were predicted in silico using SwissADME tool. In silico prediction of physicochemical properties showed that MPs had desirable lipophilic drug-like physicochemical properties including molecular weight (236 to 543), TPSA (44.76 to 179.77), lipophilicity (−0.81 to 4.14), and water solubility (−4.94 to −0.77). The pharmacokinetic properties of MPs (i.e., GIA, P-glycoprotein substrate, and CYP3A4 inhibitor) illustrated that most MPs had high intestinal absorption and bioavailability, but some MPs might cause pharmacokinetics-related drug–drug interactions. Following this, six main well-known MPs (monascin, ankaflavin, rubropunctatin, monascorubrin, rubropunctamine, monascorubramine) were selected for molecular docking with some enzyme receptors. The docking results were shown with the best molecular docking poses, and the interacting residues, number and distance of hydrogen bonds of the MPs and monacolin K (for docking with 3-hydroxy-3-methyl glutaryl coenzyme A reductase (HMG-CoA reductase)), or MPs and oleic acid (for docking with lipase). Dissociation constants showed that MPs had lower inhibitory potential for HMGR (compared with Monacolin K), and higher inhibitory potential for lipase. Individual pigments from Monascus-fermented rice, therefore, have the potential to be developed as drug candidates for controlling hyperlipidemia. Full article

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4 pages, 196 KiB

Open AccessEditorial

Enological Repercussions of Non-Saccharomyces Species 2.0

by Antonio Morata

Fermentation 2020, 6(4), 110; https://doi.org/10.3390/fermentation6040110 - 17 Nov 2020

Cited by 3 | Viewed by 1877

Abstract

Non-Saccharomyces yeast species are currently a biotechnology trend in enology and broadly used to improve the sensory profile of wines because they affect aroma, color, and mouthfeel. They have become a powerful biotool to modulate the influence of global warming on grape [...] Read more.

Non-Saccharomyces yeast species are currently a biotechnology trend in enology and broadly used to improve the sensory profile of wines because they affect aroma, color, and mouthfeel. They have become a powerful biotool to modulate the influence of global warming on grape varieties, helping to maintain the acidity, decrease the alcoholic degree, stabilize wine color, and increase freshness. In cool climates, some non-Saccharomyces can promote demalication or color stability by the formation of stable derived pigments. Additionally, non-Saccharomyces yeasts open new possibilities in biocontrol for removing spoilage yeast and bacteria or molds that can produce and release mycotoxins, and therefore, can help in reducing SO₂ levels. The promising species Hanseniaspora vineae is analyzed in depth in this Special Issue in two articles, one concerning the glycolytic and fermentative metabolisms and its positive role and sensory impact by the production of aromatic esters and lysis products during fermentation are also assessed. Full article

(This article belongs to the Special Issue Enological Repercussions of Non-Saccharomyces Species 2.0)

19 pages, 582 KiB

Open AccessReview

Yeast Cellular Stress: Impacts on Bioethanol Production

by Joshua Eardley and David J. Timson

Fermentation 2020, 6(4), 109; https://doi.org/10.3390/fermentation6040109 - 13 Nov 2020

Cited by 24 | Viewed by 5991

Abstract

Bioethanol is the largest biotechnology product and the most dominant biofuel globally. Saccharomyces cerevisiae is the most favored microorganism employed for its industrial production. However, obtaining maximum yields from an ethanol fermentation remains a technical challenge, since cellular stresses detrimentally impact on the [...] Read more.

Bioethanol is the largest biotechnology product and the most dominant biofuel globally. Saccharomyces cerevisiae is the most favored microorganism employed for its industrial production. However, obtaining maximum yields from an ethanol fermentation remains a technical challenge, since cellular stresses detrimentally impact on the efficiency of yeast cell growth and metabolism. Ethanol fermentation stresses potentially include osmotic, chaotropic, oxidative, and heat stress, as well as shifts in pH. Well-developed stress responses and tolerance mechanisms make S. cerevisiae industrious, with bioprocessing techniques also being deployed at industrial scale for the optimization of fermentation parameters and the effective management of inhibition issues. Overlap exists between yeast responses to different forms of stress. This review outlines yeast fermentation stresses and known mechanisms conferring stress tolerance, with their further elucidation and improvement possessing the potential to improve fermentation efficiency. Full article

(This article belongs to the Special Issue Biocatalysis and Fermentation—Enzyme Production and Whole Cell Biocatalysis)

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12 pages, 8461 KiB

Open AccessArticle

Application of Extractive Fermentation on the Recuperation of Exopolysaccharide from Rhodotorula mucilaginosa UANL-001L

by Carlo Franco Medina-Ramirez, Mariana Teresa Castañeda-Guel, Ma. Fernanda Alvarez-Gonzalez, Alejandro Montesinos-Castellanos, Jose Ruben Morones-Ramirez, Enrique A. López-Guajardo and Alma Gómez-Loredo

Fermentation 2020, 6(4), 108; https://doi.org/10.3390/fermentation6040108 - 13 Nov 2020

Cited by 3 | Viewed by 2194

Abstract

Exopolysaccharides (EPS) are high molecular weight biomaterials of industrial interest due to their variety of applications in the pharmaceutical, cosmetic, environmental, and food industries. EPS produced by Rhodotorula mucilaginosa UANL-001 L has sparked interest due to its bio-adsorbent and wide spectrum antimicrobial properties. [...] Read more.

Exopolysaccharides (EPS) are high molecular weight biomaterials of industrial interest due to their variety of applications in the pharmaceutical, cosmetic, environmental, and food industries. EPS produced by Rhodotorula mucilaginosa UANL-001 L has sparked interest due to its bio-adsorbent and wide spectrum antimicrobial properties. However, full exploitation and commercial application of EPS has been restrained due to low yields and high production costs. In the present work, the production and separation of EPS from Rhodotorula mucilaginosa UANL-001L was attempted through extractive fermentation in order to increase EPS production while simplifying the recovery process. Extractive fermentation was implemented with a thermoseparating polymer for phase formation (EOPO 970 and EOPO 12,000); culture viability, biomass generation, EPS production, rheological system properties, and phase formation time and temperature were monitored throughout the process. Extractive fermentation of Rhodotorula mucilaginosa UANL-001L with EOPO 970 resulted in a 42% EPS and 7% biomass recovery on the top phase after 5 to 13-min phase formation time and temperatures between 30 and 40 °C. This is the first report of extractive fermentation application for EPS production by yeast of the genera Rhodotorula, resulting in an interesting strategy for EPS production and recovery, although further optimization is needed. Full article

(This article belongs to the Special Issue Fermentation Processes to Produce Specialized Metabolites)

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15 pages, 1542 KiB

Open AccessArticle

Abatement of Inhibitors in Recycled Process Water from Biomass Fermentations Relieves Inhibition of a Saccharomyces cerevisiae Pentose Phosphate Pathway Mutant

by Nancy N. Nichols, Ronald E. Hector, Jeffrey A. Mertens and Sarah E. Frazer

Fermentation 2020, 6(4), 107; https://doi.org/10.3390/fermentation6040107 - 10 Nov 2020

Viewed by 2337

Abstract

Understanding the nature of fermentation inhibition in biomass hydrolysates and recycled fermentation process water is important for conversion of biomass to fuels and chemicals. This study used three mutants disrupted in genes important for tolerance to either oxidative stress, salinity, or osmolarity to [...] Read more.

Understanding the nature of fermentation inhibition in biomass hydrolysates and recycled fermentation process water is important for conversion of biomass to fuels and chemicals. This study used three mutants disrupted in genes important for tolerance to either oxidative stress, salinity, or osmolarity to ferment biomass hydrolysates in a xylose-fermenting Saccharomyces cerevisiae background. The S. cerevisiaeZWF1 mutant with heightened sensitivity to fermentation inhibitors was unable to ferment corn stover dilute-acid hydrolysate without conditioning of hydrolysate using a fungal strain, Coniochaeta ligniaria, to consume inhibitors. Growth of two other strains, a salt-sensitive HAL4 mutant and a GPD1 mutant sensitive to osmotic stress, was not negatively affected in hydrolysate compared to the parent xylose-metabolizing strain. In recycled fermentation process water, inhibition of the ZWF1 mutant could again be remediated by biological abatement, and no effect on growth was observed for any of the mutants compared to the parent strain. Full article

(This article belongs to the Special Issue Ethanol and Value-Added Co-Products 2.0)

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20 pages, 2263 KiB

Open AccessReview

Microbial Fermentation and Its Role in Quality Improvement of Fermented Foods

by Ranjana Sharma, Prakrati Garg, Pradeep Kumar, Shashi Kant Bhatia and Saurabh Kulshrestha

Fermentation 2020, 6(4), 106; https://doi.org/10.3390/fermentation6040106 - 06 Nov 2020

Cited by 255 | Viewed by 75128

Abstract

Fermentation processes in foods often lead to changes in nutritional and biochemical quality relative to the starting ingredients. Fermented foods comprise very complex ecosystems consisting of enzymes from raw ingredients that interact with the fermenting microorganisms’ metabolic activities. Fermenting microorganisms provide a unique [...] Read more.

Fermentation processes in foods often lead to changes in nutritional and biochemical quality relative to the starting ingredients. Fermented foods comprise very complex ecosystems consisting of enzymes from raw ingredients that interact with the fermenting microorganisms’ metabolic activities. Fermenting microorganisms provide a unique approach towards food stability via physical and biochemical changes in fermented foods. These fermented foods can benefit consumers compared to simple foods in terms of antioxidants, production of peptides, organoleptic and probiotic properties, and antimicrobial activity. It also helps in the levels of anti-nutrients and toxins level. The quality and quantity of microbial communities in fermented foods vary based on the manufacturing process and storage conditions/durability. This review contributes to current research on biochemical changes during the fermentation of foods. The focus will be on the changes in the biochemical compounds that determine the characteristics of final fermented food products from original food resources. Full article

(This article belongs to the Special Issue Probiotic Delivery through Non-Bovine Milk and Milk Products: Trends, Novelties and Benefits)

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11 pages, 1717 KiB

Open AccessArticle

Chestnut Shells as Waste Material for Succinic Acid Production from Actinobacillus succinogenes 130Z

by Michela Ventrone, Chiara Schiraldi, Giuseppe Squillaci, Alessandra Morana and Donatella Cimini

Fermentation 2020, 6(4), 105; https://doi.org/10.3390/fermentation6040105 - 06 Nov 2020

Cited by 7 | Viewed by 2294

Abstract

Currently, the full exploitation of waste materials for the production of value-added compounds is one of the potential solutions to lower costs and increase the sustainability of industrial processes. In this respect, the aim of this work was to evaluate the potential of [...] Read more.

Currently, the full exploitation of waste materials for the production of value-added compounds is one of the potential solutions to lower costs and increase the sustainability of industrial processes. In this respect, the aim of this work was to evaluate the potential of chestnut shells (CSH) as substrate for the growth of Actinobacillus succinogenes 130Z, a natural producer of succinic acid that is a precursor of several bulk chemicals with diverse applications, such as bioplastics production. Hydrolysis of ammonia pretreated CSH in citrate buffer with the Cellic CTec2 enzyme mix was optimized and strain performance was studied in bottle experiments. Data showed co-consumption of citrate, glucose and xylose, which resulted in a change of the relative ratio of produced acids, providing an insight into the metabolism of A. succinogenes that was never described to date. Furthermore, high C:N ratios seems to have a favorable impact on succinic acid production by decreasing byproduct formation. Finally, yield and volumetric production rate of succinic acid were studied in controlled 2 L bioreactors demonstrating the potential use of CSH as renewable raw material. Full article

(This article belongs to the Special Issue Fermentations as the Key Process for Bioplastic and Bioeconomy)

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14 pages, 1856 KiB

Open AccessArticle

Low-Cost Methods to Assess Beer Quality Using Artificial Intelligence Involving Robotics, an Electronic Nose, and Machine Learning

by Claudia Gonzalez Viejo and Sigfredo Fuentes

Fermentation 2020, 6(4), 104; https://doi.org/10.3390/fermentation6040104 - 31 Oct 2020

Cited by 19 | Viewed by 5107

Abstract

Beer quality is a difficult concept to describe and assess by physicochemical and sensory analysis due to the complexity of beer appreciation and acceptability by consumers, which can be dynamic and related to changes in climate affecting raw materials, consumer preference, and rising [...] Read more.

Beer quality is a difficult concept to describe and assess by physicochemical and sensory analysis due to the complexity of beer appreciation and acceptability by consumers, which can be dynamic and related to changes in climate affecting raw materials, consumer preference, and rising quality requirements. Artificial intelligence (AI) may offer unique capabilities based on the integration of sensor technology, robotics, and data analysis using machine learning (ML) to identify specific quality traits and process modifications to produce quality beers. This research presented the integration and implementation of AI technology based on low-cost sensor networks in the form of an electronic nose (e-nose), robotics, and ML. Results of ML showed high accuracy (97%) in the identification of fermentation type (Model 1) based on e-nose data; prediction of consumer acceptability from near-infrared (Model 2; R = 0.90) and e-nose data (Model 3; R = 0.95), and physicochemical and colorimetry of beers from e-nose data. The use of the RoboBEER coupled with the e-nose and AI could be used by brewers to assess the fermentation process, quality of beers, detection of faults, traceability, and authentication purposes in an affordable, user-friendly, and accurate manner. Full article

(This article belongs to the Special Issue Implementation of Digital Technologies on Beverage Fermentation)

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13 pages, 4565 KiB

Open AccessArticle

Reusability of Immobilized Cells for Subsequent Balsamic-Styled Vinegar Fermentations

by Ucrecia F. Hutchinson, Seteno K. O. Ntwampe, Boredi S. Chidi, Maxwell Mewa-Ngongang, Heinrich W. du Plessis, Mardé Booyse and Neil P. Jolly

Fermentation 2020, 6(4), 103; https://doi.org/10.3390/fermentation6040103 - 29 Oct 2020

Cited by 4 | Viewed by 2614

Abstract

Cell immobilization is a process augmentation technique aimed at improving microbial survival and activity under stressful conditions. It offers the opportunity to reuse the immobilized cells for several fermentation cycles. The present study investigated the use of recycled cells entrapped in calcium-alginate beads [...] Read more.

Cell immobilization is a process augmentation technique aimed at improving microbial survival and activity under stressful conditions. It offers the opportunity to reuse the immobilized cells for several fermentation cycles. The present study investigated the use of recycled cells entrapped in calcium-alginate beads and cells adsorbed on corncobs (CC) and oakwood chips (OWC) in subsequent fermentation cycles for balsamic-styled vinegar (BSV) production. Sugars, pH, alcohol and total acidity were monitored during fermentation. Microbial activity and product formation declined when immobilized cells were reused for the second cycle for CC and OWC fermentations. Recycled cells entrapped in Ca-alginate beads completed the second cycle of fermentations, albeit at reduced acetification rates compared to the first cycle. Scanning electron microscope (SEM) imaging results further showed a substantial the structural integrity loss for Ca-alginate beads after the first cycle, and with minor changes in the structural integrity of CC. The OWC displayed a similar morphological structure before and after the first cycle. The sensory results showed that BSV produced using immobilized cells with Ca-alginate beads and CC was palatable, while those produced using OWC had negative attributes. Ca-alginate beads offered better protection for the fermentation consortium for culture reusability in BSV fermentations. Full article

(This article belongs to the Special Issue Biocatalysis and Fermentation—Enzyme Production and Whole Cell Biocatalysis)

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23 pages, 1090 KiB

Open AccessReview

Ginger Beer: An Overview of Health Benefits and Recent Developments

by Christabel Nutakor, Justice A. Essiedu, Parise Adadi and Osman N. Kanwugu

Fermentation 2020, 6(4), 102; https://doi.org/10.3390/fermentation6040102 - 28 Oct 2020

Cited by 14 | Viewed by 20541

Abstract

Since time immemorial, ginger has been widely used as a food spice, providing aromatic odor and pungent taste, and as a medicinal plant, with various therapeutic effects such as antioxidant, anti-inflammatory, and analgesic, among others. It has long been an integral constituent of [...] Read more.

Since time immemorial, ginger has been widely used as a food spice, providing aromatic odor and pungent taste, and as a medicinal plant, with various therapeutic effects such as antioxidant, anti-inflammatory, and analgesic, among others. It has long been an integral constituent of most herbal medicines in Africa, China and India. Its medicinal properties are largely attributed to its outstanding amount of phenolics which include gingerols, paradols, zingerones, and many others. With consumer preference gradually and remarkably shifting from high-calorie towards low-calorie and functional beverages, the demand for ginger beer is flourishing at a faster rate. Currently, the ginger beer market is dominated by the United States. The demand for ginger beer is, however, debilitated by using artificial ingredients. Nonetheless, the use of natural ginger extract enriches beer with putative bioactive phytoconstituents such as shagaol, gingerone, zingerone, ginger flavonoids and essential oils, as well as essential nutritional components including proteins, vitamins and minerals, to promote general wellbeing of consumer. This paper presents an overview of the phytoconstituents of ginger as well as the overall biological activities they confer to the consumer. In addition, the market trend as well as the production technology of ginger beer using natural ginger extract is described here. Full article

(This article belongs to the Special Issue Fermentation and Bioactive Metabolites 2.0)

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13 pages, 2861 KiB

Open AccessArticle

SSR-Marker Analysis—A Method for S. cerevisiae Strain Characterization and Its Application for Wineries

by Friederike Rex, Adeline Hirschler and Maren Scharfenberger-Schmeer

Fermentation 2020, 6(4), 101; https://doi.org/10.3390/fermentation6040101 - 26 Oct 2020

Cited by 2 | Viewed by 2633

Abstract

Considering that many Saccharomyces cerevisiae strains exist and that they have different fermentation capacities, the challenge is to select the yeast strain that generates the most interesting wine character and wine flavor for the winemaker. A method based on simple sequence repeats (SSRs) [...] Read more.

Considering that many Saccharomyces cerevisiae strains exist and that they have different fermentation capacities, the challenge is to select the yeast strain that generates the most interesting wine character and wine flavor for the winemaker. A method based on simple sequence repeats (SSRs) markers, occurring in the yeast genome, was developed to differentiate the collected S.cerevisiae strains. For the amplification of the polymorphic SSR markers performed by polymerase chain reaction (PCR), two primer sets showing different size products for different S. cerevisiae strains were designed. The PCR-method with gel electrophoresis was validated using capillary sequencing and then used as a service for winegrowers combined with a sensory analysis via napping. This approach can be used for the preservation of the yeast diversity associated with given terroirs and as an option for an increased safety of fermentations. The application of S. cerevisiae strains collected in spontaneous fermentations and used for fermentation sustains the initial character of the wine and ensures a secure fermentation at the same time. Full article

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11 pages, 988 KiB

Open AccessArticle

Snapshot of Cyprus Raw Goat Milk Bacterial Diversity via 16S rDNA High-Throughput Sequencing; Impact of Cold Storage Conditions

by Eleni Kamilari, Dimitrios A. Anagnostopoulos, Photis Papademas, Marina Efthymiou, Svitlana Tretiak and Dimitrios Tsaltas

Fermentation 2020, 6(4), 100; https://doi.org/10.3390/fermentation6040100 - 24 Oct 2020

Cited by 9 | Viewed by 3277

Abstract

In general, it is a common practice among dairy producers to store the milk in the refrigerator directly after milking, in order to preserve it and prevent the development of spoilage microbes. However, the impact of keeping the milk in the refrigerator overnight [...] Read more.

In general, it is a common practice among dairy producers to store the milk in the refrigerator directly after milking, in order to preserve it and prevent the development of spoilage microbes. However, the impact of keeping the milk in the refrigerator overnight on milk microbial diversity has been poorly investigated. This study aimed to provide a snapshot of the bacterial composition of goat milk after direct storage at −80 °C and after being kept overnight at 4 °C and then in storage at −80 °, using high-throughput sequencing (HTS). Goat milk samples from four different farms were analyzed, to reveal that milk bacterial diversity differed between the two different storage conditions. Goat milk directly stored at −80 °C was characterized by the presence of the Gram-negative contaminants Pseudomonas and Acinetobacter, in addition to the genera Corynebacterium, Chryseobacterium, Bacteroides and Clostridium. Milk samples that were kept overnight at 4 °C were characterized by a reduction in their bacterial biodiversity and the predominance of the Gram-negative, aerobic Phyllobacterium. Overall, HTS methodologies provide an in-depth identification and characterization of the goat raw milk microbiome. Further, they offer a better understanding of the contribution of cold storage conditions to milk microbiota formation. This study may assist dairy producers in improving raw milk and raw milk cheeses quality and guaranteeing consumers’ safety. Full article

(This article belongs to the Special Issue Probiotic Delivery through Non-Bovine Milk and Milk Products: Trends, Novelties and Benefits)

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17 pages, 3225 KiB

Open AccessArticle

Techno-Economic Analysis of Bioethanol Plant By-Product Valorization: Exploring Market Opportunities with Protein-Rich Fungal Biomass Production

by Gülru Bulkan, Jorge A. Ferreira, Karthik Rajendran and Mohammad J. Taherzadeh

Fermentation 2020, 6(4), 99; https://doi.org/10.3390/fermentation6040099 - 21 Oct 2020

Cited by 9 | Viewed by 4967

Abstract

The feasibility of dry-grind bioethanol plants is extremely dependent on selling prices of ethanol and by-products, known as Dried distillers grains with solubles (DDGS), and sold as animal feed. Increasing the amount and quality of the by-products can widen potential feed and food [...] Read more.

The feasibility of dry-grind bioethanol plants is extremely dependent on selling prices of ethanol and by-products, known as Dried distillers grains with solubles (DDGS), and sold as animal feed. Increasing the amount and quality of the by-products can widen potential feed and food markets and improve the process economy and robustness to price fluctuations of ethanol and grain. In this study, the techno-economic analysis of a bioethanol plant was investigated. Integration of edible filamentous fungi into the process leading to the conversion of sidestreams into ethanol and protein-rich fungal biomass for food and feed applications was considered, and its impact was investigated. Sensitivity analysis considered variations on process capacity, on the price of grain and ethanol, and on the price of fungal biomass considering its use for various animal feed (e.g., pig and fish) and human food markets. Selling the fungal biomass in the human food market resulted in 5.56 times higher NPV (net present value) than the base case bioethanol plant after 20 years. Integration of a low-performing strain towards ethanol, followed by the usage of the fungal biomass in the food sector, was found to be the most resistant scenario to the low ethanol selling price and increasing grain price. This study showed that the competitiveness of ethanol plants in the fuel market could be reinforced while meeting the increasing demand for protein sources. Full article

(This article belongs to the Special Issue Ethanol and Value-Added Co-Products 2.0)

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16 pages, 12495 KiB

Open AccessArticle

Large-Scale Screening of Thiol and Fermentative Aroma Production during Wine Alcoholic Fermentation: Exploring the Effects of Assimilable Nitrogen and Peptides

by Camille Duc, Faïza Maçna, Isabelle Sanchez, Virginie Galeote, Stéphane Delpech, Anthony Silvano and Jean-Roch Mouret

Fermentation 2020, 6(4), 98; https://doi.org/10.3390/fermentation6040098 - 06 Oct 2020

Cited by 8 | Viewed by 3469

Abstract

In alcoholic fermentation, under oenological conditions, the environmental parameters impacting fermentation kinetics and aroma production have been widely studied. The nitrogen content of grape must was found to be one of the most important parameters for both of these aspects of fermentation. Many [...] Read more.

In alcoholic fermentation, under oenological conditions, the environmental parameters impacting fermentation kinetics and aroma production have been widely studied. The nitrogen content of grape must was found to be one of the most important parameters for both of these aspects of fermentation. Many studies have been performed on the effect of mineral nitrogen addition. However, it has increasingly been observed that the nature of the nitrogen added leads to different results. Our work focused on the effects of peptide addition on both fermentation kinetics and aroma production. Peptides are one of the less well understood sources of assimilable nitrogen, as their incorporation by yeast remains unclear. In this study, we compared the effect of the addition of a “classic” assimilable nitrogen source (ammonium + amino acids) with that of peptide addition in both white and red must fermentation by screening 18 Saccharomyces cerevisiae strains in total. Our data show that peptide addition enhances fermentation kinetics and leads to specific changes in the production of fermentative aromas. The impact of peptides on thiol synthesis is rather limited. Full article

(This article belongs to the Special Issue Non-Saccharomyces Yeasts as Aroma Enhancers in Fermented Products)

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12 pages, 1089 KiB

Open AccessArticle

Hydrolyzed Agricultural Residues—Low-Cost Nutrient Sources for l-Lactic Acid Production

by Susan Krull, Silvia Brock, Ulf Prüße and Anja Kuenz

Fermentation 2020, 6(4), 97; https://doi.org/10.3390/fermentation6040097 - 06 Oct 2020

Cited by 17 | Viewed by 3339

Abstract

Lactic acid is a building block for polylactic acid, which is one of the most promising polymers based on renewable resources and is used mainly in packaging industry. This bio-based polymer is biodegradable and provides an ecological and economical alternative to petrochemical plastics. [...] Read more.

Lactic acid is a building block for polylactic acid, which is one of the most promising polymers based on renewable resources and is used mainly in packaging industry. This bio-based polymer is biodegradable and provides an ecological and economical alternative to petrochemical plastics. The largest cost blocks of biotechnological lactic acid production, accounting for up to 38% of the total costs, are substrate and nutrient sources, such as peptone, meat, and yeast extract. Based on a systematic analysis of nutritional requirements, the substitution of yeast extract by low-cost protein-rich agricultural hydrolysates was estimated for the production of l-lactic acid with Lactobacillus casei. Cultivations in 24-well microtiter plates enabled analysis of nutrient requirements and the usage of various hydrolysates with a high parallel throughput and repeated sampling. Rapeseed meal (RM) and distillers’ dried grains with solubles (DDGS) were tested as low-cost protein-rich agricultural residues. By using chemically or enzymatically hydrolyzed rapeseed meal or DDGS, 70% of the nutrient sources was replaced in the fermentation process at identical productivity and product yields. All in all, the total costs of l-lactic acid production with Lactobacillus casei could potentially be reduced by up to 23%. Full article

(This article belongs to the Special Issue Lactic Acid Fermentation and the Colours of Biotechnology 2.0)

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