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To explore the feasibility of pure yeast fermentation in whole Calamondin puree (FWCP) for the utilization of the whole fruit, yeasts were isolated from naturally fermented Calamondin, and their fermentation characteristics were evaluated. The results indicated that all yeasts were able to ferment FWCP, reducing the sour taste by degrading citric acid, increasing the contents of nutrients (such as phenols and limonins) and volatile compounds, and enhancing the antioxidant activity and inhibition of α-glucosidase activity (p < 0.05). Among them, P. terricola QJJY1 and H. opuntiae QJJY14 exhibited stronger abilities to degrade organic acids, with P. terricola QJJY1 enhancing the antioxidant capacity by releasing phenolic compounds such as phloretin-3′,5′-di-c-β-glucoside, vitexin-2″-O-rhamnoside, and isomargaritene. Moreover, H. opuntiae QJJY15 improved the contents of characteristic volatile compounds such as terpene hydrocarbons and higher alcohols. In total, 70 components were identified as differential metabolites based on their fold change in the metabolites, with 42 differential metabolites involved in 29 metabolic pathways across four strains. The main pathways related to phenol and flavor enrichment were flavonoid, flavone, and flavonol biosynthesis, monoterpenoid biosynthesis, and glyoxylate and dicarboxylate metabolism. Therefore, yeast fermentation is an effective method for utilizing whole Calamondin. [ABSTRACT FROM AUTHOR]

This study aims to investigate the influence of yeast fermentation and inoculation methods on the quality of coffee across 3 different coffee cultivars. Fermenting Sacchoromyces cerevisiae SafAle s-33 on Coffea arabica cv. Caltimor via bucket inoculation outperforms spray inoculation across all aspects including microbial cell adhesion, the chemical profile, reducing sugar content and sensory analysis conducted by a Q-grader. The PCA analysis revealed distinct profiles of organic acids and volatile compounds in roasted beans in yeast fermentation and natural fermentation of all 3 coffee varieties. Particularly, volatile compounds such 1-(4-Methoxyphenyl)octan-1-one, 8-Oxabicyclo[3.2.1]oct-6-en-3-one and 5,6-Dimethoxy-2-(2-hydroxyethyl-1-thio)-3 trimethylsilyl methyl-1,4-benzoquinone and, furfuryl ethyl ether and 5-methyl furfural were detected only in yeast fermented bean. The malic acid also contained a higher amount in roasted coffee beans from the yeast fermentation of all 3 coffee varieties than the natural fermentation. Those compounds present a notably positive influence on the sensory aspects of the coffee i.e. sweet caramel, dry fruit, vanilla and hazelnut-like flavors. In addition, roasted beans from the yeast fermentation of C. arabica cv. Caltimor and C. canephora cv. Robusta displayed higher sensory scores when compared to those from natural fermentation, conversely in C. arabica cv. Bourbon, beans from both yeast fermentation and natural fermentation displayed similar quality levels. Our study concluded that the commercial yeast strain within the beer and wine industry proved to be an alternative source for coffee fermentation. Nevertheless, the selection of the coffee variety plays a crucial role when utilizing S. cerevisiae SafAle s-33 as a starter. [ABSTRACT FROM AUTHOR]

Summary: In this study, a novel frozen pasta product (direct‐fried yeast‐fermented frozen youtiao, DFYF‐frozen youtiao) was developed, and its quality deterioration mechanism was explored from gluten. The comprehensive quality assessment revealed that DFYF‐frozen youtiao essentially satisfied consumers' expectations. However, after 10 freeze–thawed cycles (FTc), its specific volume dropped, accompanied by an 83.3% reduction in gas production capacity. Meanwhile, FTc treatment resulted in a noticeable decrease in springiness and resilience, and increased the hardness and springiness by 32.8% and 44.5% respectively. The deterioration of rheological properties for DFYF‐frozen youtiao dough during FTc was attributed to the loose gluten network, as evidenced by glutenin macropolymer depolymerisation, high hydrophobicity and weak thermal stability of gluten proteins. This study aims to offer technical guidance for producing palatable frozen youtiao with enhanced health attributes and understand the intricate relationships between the characteristics of gluten proteins and quality of DFYF‐frozen youtiao. [ABSTRACT FROM AUTHOR]

Abstract Background The textile industry has several negative impacts, mainly because it is based on a linear business model that depletes natural resources and produces excessive amounts of waste. Globally, about 75% of textile waste is disposed of in landfills and only 25% is reused or recycled, while less than 1% is recycled back into new garments. In this study, we explored the valorisation of cotton fabric waste from an apparel textile manufacturing company as valuable biomass to produce lactic acid, a versatile chemical building block. Results Post-industrial cotton patches were pre-treated with the aim of developing a methodology applicable to the industrial site involved. First, a mechanical shredding machine reduced the fabric into individual fibres of maximum 35 mm in length. Afterwards, an alkaline treatment was performed, using NaOH at different concentrations, including a 16% (w/v) NaOH enriched waste stream from the mercerisation of cotton fabrics. The combination of chemo-mechanical pre-treatment and enzymatic hydrolysis led to the maximum recovery yield of 90.46 ± 3.46%, corresponding to 74.96 ± 2.76 g/L of glucose released, which represents a novel valorisation of two different side products (NaOH enriched wastewater and cotton textile waste) of the textile industry. The Saccharomyces cerevisiae strain CEN.PK m850, engineered for redirecting the natural alcoholic fermentation towards a homolactic fermentation, was then used to valorise the glucose-enriched hydrolysate into lactic acid. Overall, the process produced 53.04 g/L ± 0.34 of l-lactic acid, with a yield of 82.7%, being the first example of second-generation biomass valorised with this yeast strain, to the best of our knowledge. Remarkably, the fermentation performances were comparable with the ones obtained in the control medium. Conclusion This study validates the exploitation of cotton post–industrial waste as a possible feedstock for the production of commodity chemicals in microbial cell-based biorefineries. The presented strategy demonstrates the possibility of implementing a circular bioeconomy approach in manufacturing textile industries. Graphical Abstract

The aim of this research was to optimize the production process of fermented gluten-free quinoa bread. To this end, the effect of different hydrocolloids on the technological, fermentative, and nutritional properties of quinoa-based gluten-free doughs and breads was evaluated. For this purpose, 3% of four different hydrocolloids (sodium alginate, k-carrageenan, xanthan gum, and hydroxypropyl methylcellulose (HPMC)) were used in gluten-free doughs composed of 50% quinoa flour, 20% rice flour, and 30% potato starch. The rheological and fermentative properties of the doughs were evaluated, as well as the chemical composition, specific volume, crust and crumb color, and alveolar structure profile of gluten-free breads. The results highlighted the differences in dough rheology during mixing and fermentation of the doughs. In particular, HPMC showed a good gas retention (93%) during the fermentation of quinoa dough by registering the highest maximum dough development height (Hm). The gluten-free quinoa breads obtained were characterized by significantly different quality parameters (p < 0.05). The use of 3% HPMC resulted in breads with the lowest baking loss, the highest volume, and the most open crumb structure. [ABSTRACT FROM AUTHOR]

Xylanase is an essential component used to hydrolyze the xylan in wheat flour to enhance the quality of bread. Presently, cold-activated xylanase is popularly utilized to aid in the development of dough. In this study, ancestral sequence reconstruction and molecular docking of xylanase and wheat xylan were used to enhance the activity and stability of a thermophilic xylanase. The results indicated that the ancestral enzyme TmxN3 exhibited significantly improved activity and thermal stability. The Vmax increased by 2.7 times, and the catalytic efficiency (Kcat/Km) increased by 1.7 times in comparison to TmxB. After being incubated at 100 °C for 120 min, it still retained 87.3% of its activity, and the half-life in 100 °C was 330 min, while the wild type xylanase was only 55 min. This resulted in an improved shelf life of bread, while adding TmxN3 considerably enhanced its quality with excellent volume and reduced hardness, chewiness, and gumminess. The results showed that the hardness was reduced by 55.2%, the chewiness was reduced by 40.11%, and the gumminess was reduced by 53.52%. To facilitate its industrial application, we further optimized the production conditions in a 5L bioreactor, and the xylanase activity reached 1.52 × 106 U/mL culture. [ABSTRACT FROM AUTHOR]

Background: The textile industry has several negative impacts, mainly because it is based on a linear business model that depletes natural resources and produces excessive amounts of waste. Globally, about 75% of textile waste is disposed of in landfills and only 25% is reused or recycled, while less than 1% is recycled back into new garments. In this study, we explored the valorisation of cotton fabric waste from an apparel textile manufacturing company as valuable biomass to produce lactic acid, a versatile chemical building block. Results: Post-industrial cotton patches were pre-treated with the aim of developing a methodology applicable to the industrial site involved. First, a mechanical shredding machine reduced the fabric into individual fibres of maximum 35 mm in length. Afterwards, an alkaline treatment was performed, using NaOH at different concentrations, including a 16% (w/v) NaOH enriched waste stream from the mercerisation of cotton fabrics. The combination of chemo-mechanical pre-treatment and enzymatic hydrolysis led to the maximum recovery yield of 90.46 ± 3.46%, corresponding to 74.96 ± 2.76 g/L of glucose released, which represents a novel valorisation of two different side products (NaOH enriched wastewater and cotton textile waste) of the textile industry. The Saccharomyces cerevisiae strain CEN.PK m850, engineered for redirecting the natural alcoholic fermentation towards a homolactic fermentation, was then used to valorise the glucose-enriched hydrolysate into lactic acid. Overall, the process produced 53.04 g/L ± 0.34 of l-lactic acid, with a yield of 82.7%, being the first example of second-generation biomass valorised with this yeast strain, to the best of our knowledge. Remarkably, the fermentation performances were comparable with the ones obtained in the control medium. Conclusion: This study validates the exploitation of cotton post–industrial waste as a possible feedstock for the production of commodity chemicals in microbial cell-based biorefineries. The presented strategy demonstrates the possibility of implementing a circular bioeconomy approach in manufacturing textile industries. [ABSTRACT FROM AUTHOR]

Securing "energy from waste" appeared as the most engrossed research area to find out global solutions for waste disposal and energy production. Watermelon peels (WMPs) are discarded as bulk waste in the whole oriental region that demands appropriate disposal to save environment from pollution. This study investigates the potential of yeast employing WMPs that embodies significant sugars to be fermented into ethanol. For this purpose, WMPs were subjected to dilute sulfuric acid hydrolysis under optimized conditions (6% H2SO4 at 50 °C for 60 min) elucidated by response surface methodology (RSM) of central composite design (CCD). The experimental design dealt with the optimization of fermentation influencing independent parameters which included pretreated WMP hydrolysate, synthetic medium ratio (X1), hydrolysis temperature (X2), and incubation period (X3) for maximal ethanol yield while employing standard (Saccharomyces cerevisiae K7) and experimental (Metchnikowia cibodasensis Y34) yeast isolates. The significance of the model for experimental yeast was envisaged by 6.22 F value (0.0060 P), 0.8616 R2 and 8.393 adequate precision. The optimized parameters were found as 52.03 mL WMP hydrolysate concentration at 29.46 °C after an incubation period of 15 days. Maximal ethanol yield (g/g reducing sugars) obtained from Saccharomyces cerevisiae K7 was 0.33 ± 0.05, while Metchnikowia cibodasensis Y34 showed as 0.38 ± 0.01. From this research, the ethanologenic and ethanol tolerant potential of yeast Metchnikowia cibodasensis Y34 is apparent to valorize WMPs. [ABSTRACT FROM AUTHOR]

This research paper addresses the hypotheses that Kluyveromyces marxianus can be cultured with good alcohol production on different whey-derived matrices, and that the fermented product can be used in order to develop alcoholic beverages with acceptable sensory characteristics by mixtures with yeast-fermented fruit-based matrices. Growth and fermentative characteristics of Kluyveromyces marxianus LFIQK1 in different whey-derived matrices were explored by culturing (24 h, 30°C) on reconstituted whey, demineralized whey, heat-treated whey and milk permeate media. High lactose consumption, ethanol production and yield were observed. Reconstituted whey matrix was selected for mixing with orange or strawberry juices fermented using Saccharomyces cerevisiae to obtain alcoholic beverages (W-OR and W-ST, respectively). Consumer evaluation of beverages was performed using acceptability and Check-All-That-Apply (CATA) questions. Good acceptance was observed, significantly higher for W-ST than for W-OR. CATA questions gave information about organoleptic characteristics of beverages. Penalty analysis showed W-R and W-ST were positively associated with smooth/refreshing and fruity/natural, respectively. Liking was represented, accordingly with penalty analysis, by natural/refreshing. A novel alternative for utilization of whey and whey-related matrices by alcoholic beverages production with natural ingredients is presented. [ABSTRACT FROM AUTHOR]

Deep Ocean Water (DOW) is rich in minerals and serves as a natural source of nutrients. However, due to the inorganic nature of these minerals, cultivating yeast in DOW could aid in the fermentation process, and simultaneously, the yeast can assimilate the minerals from DOW, resulting in a mineral-enriched yeast biomass. Focusing on three DOW sources off the eastern coast of Taiwan (TT-1, HL-1, HL-2), we fermented various yeast strains of Saccharomyces cerevisiae. Therefore, this study investigates the effects of DOW on yeast growth, alcohol dehydrogenase activity, and the biological absorption of mineral ions by the yeast. Additionally, this research employs two-dimensional electrophoresis techniques to examine how the absorbed minerals influence the regulation of yeast proteins, thereby affecting biomass and metabolism. In the result, S. cerevisiae BCRC 21689 demonstrated a remarkable ability to bio-absorb minerals such as magnesium, calcium, potassium, and zinc from DOW, enhancing its growth and fermentation performance. Proteomic analysis revealed significant shifts in the expression of 21 proteins related to glycolytic and energy metabolism, alcohol metabolism, and growth regulation, all influenced by DOW's mineral-rich environment. This indicates that DOW's mineral content is a key factor in upregulating essential enzymes in glycolytic metabolism and alcohol dehydrogenase. An increase in proteins involved in synthesis and folding processes was also observed, leading to a substantial increase in yeast biomass. This study underscores the potential of DOW as a natural enhancer in yeast fermentation processes, enriching the yeast with diverse minerals and modulating proteomic expression to optimize yeast growth and fermentation.

To explore the effects of yeast fermentation on deodorization and flavor enhancement of Seriola lalandi roe, the nutritional value of Seriola lalandi roe were studied in this paper at first, and then high sugar type instant dry yeast was selected as the fermenting agent, the optimal fermentation process conditions were optimized by single-factor experimental analysis according to the sensory score, pH and total acid content. Fresh fish roe and unfermented fish roe were used as controls to analyze the difference in sensory quality, free amino acids and volatile flavor composition of the fermented fish roe. The results showed that, the Seriola lalandi roe was rich in polyunsaturated fatty acids, zinc and selenium elements, and had high nutritional value. The best deodorization effect by 1.5% yeast inoculum, 5% sucrose addition, 1.5 h fermentation time and 28 ℃ fermentation temperature. The contents of sweet amino acids and umami amino acids in fermented roe increased significantly（P

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This research aimed to assess how the partial removal of carbon dioxide affects fermentations to provide a better understanding of how the manipulation of carbon dioxide concentration can be used to optimize industrial fermentations. To achieve this, fermentation kinetics, fermentation metabolic products, and yeast stress indicators were analyzed throughout ongoing brewing fermentations conducted under partial vacuum with atmospheric pressure controls. The partial vacuum reduced the solubility of carbon dioxide in the media and decreased the time necessary to reach carbon dioxide saturation. The effect was an increased rate of fermentation, and significantly more viable cells produced under vacuum pressure compared to controls. Ethanol, glycerol, and volatile organic compound concentrations were all significantly increased under partial vacuum, while indicators of yeast stress (trehalose) were reduced. Additionally, as the number of yeast cells was higher under partial vacuum, less sugar was consumed per volume of yeast cell. This study measured fermentation kinetics, metabolic products, and yeast health to holistically assess the effect of partial vacuum during a batch fermentation and found significant differences in each that can be individually exploited by researchers and industry. Summary An exploration of batch yeast fermentation in a low-pressure environment, with a focus on the health and productivity of the yeast cells. [ABSTRACT FROM AUTHOR]

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The importance of Saccharomyces cerevisiae yeast cells is known worldwide, as they are the most used microorganisms in biotechnology for bioethanol and biofuel production. Also, they are analyzed and studied for their similar internal biochemical processes to human cells, for a better understanding of cell aging and response to cell stressors. The special ability of S. cerevisiae cells to develop in both aerobic and anaerobic conditions makes this microorganism a viable model to study the transformations and the way in which cellular metabolism is directed to face the stress conditions due to environmental changes. Thus, this review will emphasize the effects of oxidative, ethanol, and osmotic stress and also the physiological and genetic response of stress mitigation in yeast cells. [ABSTRACT FROM AUTHOR]

The aim of this research was to optimize the production process of fermented gluten-free quinoa bread. To this end, the effect of different hydrocolloids on the technological, fermentative, and nutritional properties of quinoa-based gluten-free doughs and breads was evaluated. For this purpose, 3% of four different hydrocolloids (sodium alginate, k-carrageenan, xanthan gum, and hydroxypropyl methylcellulose (HPMC)) were used in gluten-free doughs composed of 50% quinoa flour, 20% rice flour, and 30% potato starch. The rheological and fermentative properties of the doughs were evaluated, as well as the chemical composition, specific volume, crust and crumb color, and alveolar structure profile of gluten-free breads. The results highlighted the differences in dough rheology during mixing and fermentation of the doughs. In particular, HPMC showed a good gas retention (93%) during the fermentation of quinoa dough by registering the highest maximum dough development height (Hm). The gluten-free quinoa breads obtained were characterized by significantly different quality parameters (p < 0.05). The use of 3% HPMC resulted in breads with the lowest baking loss, the highest volume, and the most open crumb structure.

Xylanase is an essential component used to hydrolyze the xylan in wheat flour to enhance the quality of bread. Presently, cold-activated xylanase is popularly utilized to aid in the development of dough. In this study, ancestral sequence reconstruction and molecular docking of xylanase and wheat xylan were used to enhance the activity and stability of a thermophilic xylanase. The results indicated that the ancestral enzyme TmxN3 exhibited significantly improved activity and thermal stability. The Vmax increased by 2.7 times, and the catalytic efficiency (Kcat/Km) increased by 1.7 times in comparison to TmxB. After being incubated at 100 °C for 120 min, it still retained 87.3% of its activity, and the half-life in 100 °C was 330 min, while the wild type xylanase was only 55 min. This resulted in an improved shelf life of bread, while adding TmxN3 considerably enhanced its quality with excellent volume and reduced hardness, chewiness, and gumminess. The results showed that the hardness was reduced by 55.2%, the chewiness was reduced by 40.11%, and the gumminess was reduced by 53.52%. To facilitate its industrial application, we further optimized the production conditions in a 5L bioreactor, and the xylanase activity reached 1.52 × 106 U/mL culture.

Whey is a dairy residue generated during the production of cheese and yogurt. Whey contains mainly lactose and proteins, contributing to its high chemical oxygen demand (COD). Current environmental regulations request proper whey disposal to avoid environmental pollution. Whey components can be transformed by yeast into ethanol and biomolecules with aroma and flavor properties, for example, 2-phenyethanol (2PE), highly appreciated in the industry due to its organoleptic and biocidal properties. The present study aimed to valorize agri-food residues in 2PE by developing suitable bioprocess. Cheese whey was used as substrate source, whereas crab headshells, residual soy cake, and brewer's spent yeast (BSY) were used as renewable nitrogen sources for the yeasts Kluyveromyces marxianus and Debaryomyces hansenii. The BSYs promoted the growth of both yeasts and the production of 2PE in flask fermentation. The bioprocess scale-up to 2 L bioreactor allowed for obtaining a 2PE productivity of 0.04 g2PE/L·h, twofold better productivity results compared to the literature. The bioprocess can save a treatment unit because the whey COD decreased under the detection limit of the analytical method, which is lower than environmental requirements. In this way, the bioprocess prevents environmental contamination and contributes to the circular economy of the dairy industry. [ABSTRACT FROM AUTHOR]

Recombinant collagen production, especially using yeasts as expression systems, could represent a promising alternative over traditional extractive methods from animal sources, offering controllable, scalable, and high-quality products. Monitoring the efficiency and efficacy of procollagen/collagen expression, especially in the initial fermentation phases, can be difficult and time consuming, as biological matrices necessitate purification and commonly used analytical methods are only partially informative. We propose a straightforward, efficient, and reusable immunocapture system able to specifically isolate human procollagen type II from fermentation broths and to release it in few experimental steps. A recovered sample allows for a detailed characterization providing information on structural identity and integrity, which can strongly support the monitoring of fermentation processes. The immunocapture system relies on the use of protein A–coated magnetic beads which have been functionalized and cross-linked with a human anti-procollagen II antibody (average immobilization yield of 97.7%) to create a stable and reusable support for the specific procollagen fishing. We set up the binding and release conditions ensuring specific and reproducible binding with a synthetic procollagen antigen. The absence of non-specific interaction with the support and binding specificity was demonstrated, and the latter was also confirmed by a peptide mapping epitope study in reversed-phase liquid chromatography high-resolution mass spectrometry (RP-LC-HRMS). The bio-activated support proved to be reusable and stable over 21 days from the initial use. Finally, the system was successfully tested on a raw yeast fermentation sample to provide a proof of concept of the applicability within recombinant collagen production. [ABSTRACT FROM AUTHOR]

The increase in the wastage of bread, representing 12.5 million tons per year, causes ecological problems, such as the production of methane and CO2, when that waste bread (WB) is improperly managed. To reduce this ecological footprint, a more sustainable system of WB management must be set up. Based on its chemical composition, WB has a high potential to be used as feedstock for microbial growth and conversion into value-added bio products. The microbial valorisation of WB is a novel biotechnological approach to upgrading a waste into a renewable feedstock for bio-based industry, thus favouring the circular economy concept. Based on this, the aim of this study was to test WB as a feedstock for biomass production by Yarrowia lipolytica, which can be considered as a promising supplement for animal and human dietary products. The enzymatic hydrolysis of WB was primarily optimized for large-scale production in a bioreactor. The biomass production of Y. lipolytica strain K57 on WB hydrolysate-based media in batch bioreactor culture was then investigated. As a result, a very high starch to glucose conversion yield of 97% was obtained throughout optimised hydrolysis. At the end of 47 h of batch culture, a biomass higher than 62 g/L, specific growth rate of 0.37 h−1 and biomass yield of 0.45 g/g were achieved from a WB hydrolysate. Therefore, this study demonstrates that WB hydrolysate has a promising potential to be used as a feedstock for biomass production by Y. lipolytica strain K57 for food and animal diet applications. [ABSTRACT FROM AUTHOR]

Abstract Background Lignocellulose is a valuable carbon source for the production of biofuels and biochemicals, thus having the potential to substitute fossil resources. Consolidated bio-saccharification (CBS) is a whole-cell-based catalytic technology previously developed to produce fermentable sugars from lignocellulosic agricultural wastes. The deep-sea yeast strain Rhodotorula paludigena P4R5 can produce extracellular polyol esters of fatty acids (PEFA) and intracellular single-cell oils (SCO) simultaneously. Therefore, the integration of CBS and P4R5 fermentation processes would achieve high-value-added conversion of lignocellulosic biomass. Results The strain P4R5 could co-utilize glucose and xylose, the main monosaccharides from lignocellulose, and also use fructose and arabinose for PEFA and SCO production at high levels. By regulating the sugar metabolism pathways for different monosaccharides, the strain could produce PEFA with a single type of polyol head. The potential use of PEFA as functional micelles was also determined. Most importantly, when sugar-rich CBS hydrolysates derived from corn stover or corncob residues were used to replace grain-derived pure sugars for P4R5 fermentation, similar PEFA and SCO productions were obtained, indicating the robust conversion of non-food corn plant wastes to high-value-added glycolipids and lipids. Since the produced PEFA could be easily collected from the culture via short-time standing, we further developed a semi-continuous process for PEFA production from corncob residue-derived CBS hydrolysate, and the PEFA titer and productivity were enhanced up to 41.1 g/L and 8.22 g/L/day, respectively. Conclusions Here, we integrated the CBS process and the P4R5 fermentation for the robust production of high-value-added PEFA and SCO from non-food corn plant wastes. Therefore, this study suggests a feasible way for lignocellulosic agro-waste utilization and the potential application of P4R5 in industrial PEFA production.

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Rapeseed meal (RM) is produced in large quantities as a byproduct of oil extraction from rapeseeds. However, the efficient utilization of RM as animal feed is limited by its low metabolizable energy, poor palatability, and high levels of fiber and anti-nutritional components. Here, we investigate the potential of enriching RM with single-cell protein through fermentation with conventional and unconventional yeasts. The process of simultaneous saccharification and fermentation improved the parameters of the waste biomass, especially the protein content, while reducing the amount of crude fiber and enhancing the biotransformation of isoflavone compounds present in the waste. Fermentation yielded the highest protein gain for the Saccharomyces cerevisiae Ethanol Red strain (ΔN = 2.38%) at a biomass load of 12.5 g and for Scheffersomyces stipitis (ΔN = 2.34%) at an enzyme dose of 0.125 mL/10 g DM. The crude fiber content (CF) was reduced by 2.55–7.18%. The simultaneous saccharification and fermentation (SSF) process resulted in the conversion of isoflavones to forms with fewer adverse effects and a lower estrogenic activity. The results show the potential of using RM as a substrate for making a nutritionally improved feed components. [ABSTRACT FROM AUTHOR]

Cotton stalk is the most widely generated agricultural residue with lower economic importance, and can be employed as a feedstock in lignocellulosic biorefinery for the manufacture of bioethanol and other value-added bioproducts. Cotton stalk possesses high holocellulose content, which can be saccharified to various fermentable sugars for bioethanol production. However, the occurrence of high amount of lignin in cotton stalk renders it an inferior substrate for bioethanol production. Selection of suitable pretreatment process can improve digestibility of cotton stalk and hence higher sugar concentration on subsequent enzymatic saccharification. Furthermore, fermentation of hexose and pentoses sugars to ethanol requires robust microbial strains and efficient fermentation methods. Therefore, the major hindrance in commercializing lignocellulosic ethanol from cotton stalk is to develop an effective combination of pretreatment, saccharification, and fermentation methods thereby making the whole bioconversion process economically viable. This review paper discusses various previously investigated pretreatment, acid and/or enzymatic saccharification, and fermentation methods for cotton stalk-to-lignocellulosic ethanol production. Finally, it also discusses the major barriers in bioethanol fermentation strategies, and as well future perspectives to overcome these issues. [ABSTRACT FROM AUTHOR]

With the aim to exhibit the advantages of catalytic accelerator in enhancing the selective hydrolysis of cellulose to sugar, cellulose is hydrolyzed in low acid aqueous system with catalytic accelerator. And then sugar products are extracted and fermented by yeast. By the assistance of catalytic accelerator, cellulose conversion rate and total reducing sugar yield are 95.7% and 90.9%. And the glucose yield is as high as 73.6%. The sugar products with high glucose content can be easily extracted from cellulose hydrolysate. Low toxicity of the sugar products to yeast is found during yeast fermentation. The glucose in cellulose hydrolysate can be fully consumed after 12 h. A highly actual ethanol yield is exhibited, which is equal to the actual yield level of standard glucose solution. The important role of catalytic accelerator in aqueous hydrolytic system to produce fermentable sugar is clearly reflected. Furthermore, a simple but effective way is established to efficient utilization of cellulose as an applicable carbon source for the conversion of more value-added chemicals and materials. [ABSTRACT FROM AUTHOR]

Accurate monitoring of dissolved oxygen (DO) is vital for aerobic fermentation process control. This work presents an autoclavable Micro-Dissolved oxygen Sensor (MDS) that can monitor real time DO. The proposed sensor is much cheaper to be manufactured (< $35) and can be adapted to varying measurement environments. An ultra-micropore matrix was created using femtosecond laser processing technology to reduce flow dependency of probe signals. The validity of the proposed DO sensor was verified by testing it under different DO levels. The result revealed consistency between the new designed sensor and a commercial DO sensor. The obtained sensitivity was− 7.93 μA·L·mg−1 (MDS with ultra-micropore matrix). Moreover, the MDS can function without an oxygen-permeable membrane and a solid electrolyte was used which reduced the response time (4.6 s). For real-time monitoring, the stability of the MDS was validated during a yeast batch fermentation carried out until 18 h. [ABSTRACT FROM AUTHOR]

Copyright of China Brewing is the property of China Brewing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Summary: The effect of sucrose levels on the rheo‐fermentation properties of dough were studied. Compared with control group, dough forming time and dough strength were enhanced in the sucrose dough, and the water absorption and development time were significantly reduced. Dough with 10% sucrose had the highest resistance, and 4% and 10% sucrose increased the toughness of the dough. 2% sucrose dough had the better leavening ability. There was lower strong bound water dough and higher weakly bound water in 2% sucrose dough compared with the other sucrose dough. With increasing sucrose levels, the content of free water in dough increased significantly. There was no growth of yeast in the sugar‐free medium (0%), 2% sucrose was much more suitable for yeast growth, while 6% and 10% sucrose levels inhibited yeast growth. Compared with 2% sucrose group, yeast produced more glycerol content and ethanol content in 6% and 10% sucrose medium. In conclusion, 2% sucrose dough had a better and smoother development fermentability, and a better yeast growth, sucrose levels affected the rheological properties of dough by affecting the migration and distribution of water, growth and metabolites of yeast. [ABSTRACT FROM AUTHOR]

Maize accumulates large amounts of starch in seeds which have been used as food for human and animals. Maize starch is an importantly industrial raw material for bioethanol production. One critical step in bioethanol production is degrading starch to oligosaccharides and glucose by α-amylase and glucoamylase. This step usually requires high temperature and additional equipment, leading to an increased production cost. Currently, there remains a lack of specially designed maize cultivars with optimized starch (amylose and amylopectin) compositions for bioethanol production. We discussed the features of starch granules suitable for efficient enzymatic digestion. Thus far, great advances have been made in molecular characterization of the key proteins involved in starch metabolism in maize seeds. The review explores how these proteins affect starch metabolism pathway, especially in controlling the composition, size and features of starch. We highlight the roles of key enzymes in controlling amylose/amylopectin ratio and granules architecture. Based on current technological process of bioethanol production using maize starch, we propose that several key enzymes can be modified in abundance or activities via genetic engineering to synthesize easily degraded starch granules in maize seeds. The review provides a clue for developing special maize cultivars as raw material in the bioethanol industry. [ABSTRACT FROM AUTHOR]

In this study the combinatory effect of several extrinsic factors on reduced (vacuum) pressure fermentations was explored. Specifically, the pressure, temperature, and FAN levels of high gravity Saccharomyces cerevisiae fermentations were manipulated, while yeast morphology was assessed using automated multivariate image analysis. Fermentation attributes including yeast growth, viability, and ethanol production were monitored using standard methods. Across all FAN and temperature levels, reduced pressure (vacuum pressure) fermentations resulted in a greater than or equal number of cells in suspension, higher average viability, and greater ethanol production in comparison to atmospheric pressure fermentations; however, the magnitude of the effect varied with extrinsic factors. The image analysis revealed that while yeast size was extremely variable across all fermentations, the ratio of vacuole to cell area consistently decreased over each fermentation and could be used to predict the point where the yeast experienced a sharp decline in viability ending the fermentation. This study showed that a combination of traditional measurements and novel automated analyses can be used by brewers to anticipate performance and endpoints of their fermentations, and that reduced pressure can have significant effects upon the rate and final ethanol concentration of variable industrial fermentations. [ABSTRACT FROM AUTHOR]

Background: Lignocellulose is a valuable carbon source for the production of biofuels and biochemicals, thus having the potential to substitute fossil resources. Consolidated bio-saccharification (CBS) is a whole-cell-based catalytic technology previously developed to produce fermentable sugars from lignocellulosic agricultural wastes. The deep-sea yeast strain Rhodotorulapaludigena P4R5 can produce extracellular polyol esters of fatty acids (PEFA) and intracellular single-cell oils (SCO) simultaneously. Therefore, the integration of CBS and P4R5 fermentation processes would achieve high-value-added conversion of lignocellulosic biomass. Results: The strain P4R5 could co-utilize glucose and xylose, the main monosaccharides from lignocellulose, and also use fructose and arabinose for PEFA and SCO production at high levels. By regulating the sugar metabolism pathways for different monosaccharides, the strain could produce PEFA with a single type of polyol head. The potential use of PEFA as functional micelles was also determined. Most importantly, when sugar-rich CBS hydrolysates derived from corn stover or corncob residues were used to replace grain-derived pure sugars for P4R5 fermentation, similar PEFA and SCO productions were obtained, indicating the robust conversion of non-food corn plant wastes to high-value-added glycolipids and lipids. Since the produced PEFA could be easily collected from the culture via short-time standing, we further developed a semi-continuous process for PEFA production from corncob residue-derived CBS hydrolysate, and the PEFA titer and productivity were enhanced up to 41.1 g/L and 8.22 g/L/day, respectively. Conclusions: Here, we integrated the CBS process and the P4R5 fermentation for the robust production of high-value-added PEFA and SCO from non-food corn plant wastes. Therefore, this study suggests a feasible way for lignocellulosic agro-waste utilization and the potential application of P4R5 in industrial PEFA production. [ABSTRACT FROM AUTHOR]

This study aimed to explore the potential of a fermentation technology to reduce off-flavour perception and its underlying mechanisms. Results revealed that yeast fermentation (YF) significantly ameliorated the off-flavour of pig liver (p < 0.05). Specifically, YF pre-treatment decreased the relative abundance of α-helix and fluorescence intensity while increasing the surface hydrophobicity and S S level and loosening the microstructure of myofibrillar proteins (MPs) in pig liver. Additionally, the appropriate fermentation treatments enhanced the MP–aldehyde binding capacity by 0.25–1.30 times, demonstrating that YF-induced conformational modifications in pig liver proteins made them more prone to interacting with characteristic aldehydes. Moreover, molecular docking results confirmed that hydrophobic interactions are the primary drivers of MP–aldehyde binding. These findings suggest that YF technology holds immense promise for modulating off-flavour perception in liver products by altering protein conformation. • Yeast fermentation altered the secondary, tertiary structures and microstructure of PLPs. • Yeast fermentation enhanced the binding ability of aldehydes to PLPs. • PLPs bound to 5 characteristic aldehydes via non-covalent interactions. • The flavour regulation of PL could be achieved by fermentation. [ABSTRACT FROM AUTHOR]

The solidification of wheat dough is induced by a complex sequence of polymer transition processes. The extend of the polymer transitions is thereby strongly dependent on the hydration level of each constituent. Further, yeast metabolites, resulting from the fermentation of dough, are hypothesized to impact the functionality of dough's polymers in their thermal transitional behavior. Hence, the aim of this work was to elucidate the occurrence of polymer transitions in dependency of (i) the amount of water available for hydration and (ii) the presence of yeast metabolites. An approach of reduced complexity was chosen to reveal the interactions during the hydrothermal treatment by multiwave SAOS rheology together with basic physicochemical characterization methods (DSC, 1H NMR). By excluding single dough polymers from the solidification cascade, their functionality in the polymeric system was elucidated. In combination with a non-invasive yeast inactivation method, sophisticated information on the dependence of the matrix solidification on the matrix hydration level and presence of yeast metabolites were established. Water shortage was shown to limit the extend of starch gelatinization, resulting in a reduced overall matrix solidification, whereas the extend of gluten polymerization was not affected by water shortage. In contrast, a water surplus favored the progression of starch gelatinization, which was also shown to be induced indirectly by yeast metabolites. Therefore, the water availability and accessibility of starch were shown to be decisive for the solidification of the dough matrix. The knowledge obtained contributes to the elucidation of the impact of baker's yeast on the dough matrix. [Display omitted] • Artificial re-engineered starch–gluten systems favor progression of gelatinization • Water shortage more restrictive for gelatinization than for gluten polymerization • Increasing hydration enables more short range interaction during the baking process • Destabilizing effects of yeast metabolites likely based in gluten microstructure • Underdeveloped dough systems less impaired by degradation by yeast metabolites [ABSTRACT FROM AUTHOR]

The importance of Saccharomyces cerevisiae yeast cells is known worldwide, as they are the most used microorganisms in biotechnology for bioethanol and biofuel production. Also, they are analyzed and studied for their similar internal biochemical processes to human cells, for a better understanding of cell aging and response to cell stressors. The special ability of S. cerevisiae cells to develop in both aerobic and anaerobic conditions makes this microorganism a viable model to study the transformations and the way in which cellular metabolism is directed to face the stress conditions due to environmental changes. Thus, this review will emphasize the effects of oxidative, ethanol, and osmotic stress and also the physiological and genetic response of stress mitigation in yeast cells.

Crumbly dough fermentation was applied to produce dried hollow noodles, with Lactobacillus plantarum, Koji and yeast as the main fermenting agents. The cooking, textural and digestive properties of the noodles were studied, followed by the morphological, crystalline and thermal properties of the starch. The results show that, compared to unfermented noodles, the optimal cooking time of Koji pre-fermented noodles (KJHN) decreased from 460 s to 253 s, and they possessed a higher percentage of weakly bound water and degree of gelatinization at the same cooking time. After cooking, KJHN had a softer texture and higher starch digestibility. In addition, the physicochemical properties of the KJHN and Lactobacillus plantarum pre-fermented noodles (LPHN) showed a decrease in pH and amylose content, and an increase in reducing sugars content. The starch extracted from KJHN and LPHN had significant superficial erosion and pore characteristics, and the gelatinization enthalpy, relative crystallinity and short-range order were all increased. These changes in the starch properties and the quality characteristics of noodles resulting from Koji fermentation might provide a reference for the development of easy-to-cook and easy-to-digest noodles. [ABSTRACT FROM AUTHOR]

Consumption of wholegrain cereal and pseudocereal products is connected with several health benefits, primarily due to their high dietary fibre (DF) content. However, increased DF content in flour can lead to adverse changes in technological properties of dough and final bakery product. Various biotechnological tools can alleviate these changes, resulting in easier processing and better sensory quality of products. The purpose of this review is to critically assess biotechnological tools for dietary fibre modification in the bakery products creation, with determination of advantages and disadvantages of each biotechnological approach. These tools have been coming into spotlight in the recent years, due to their numerous advantages which include mild processing conditions, specific and/or targeted effect and wide scope of application. Based on the current literature, biotechnological tools include the application of various enzymes and microbial fermentation. Endogenous enzymes are synthesized during grain germination, thus affecting the chemical composition and processing characteristics of grains. Exogenous enzymes are often added as processing aids; however, their application increase production costs. Dietary fibre modification by fermentation processes is used to improve product texture, increase the nutritional value and digestibility of bakery products by reduction of antinutrients. On the other hand, most fermentation processes are time- and energy-consuming and, in the case of solid-state fermentation, prone to contamination by moulds. The application of biotechnological processing allows the use of less utilized cereals and their by-products, thus improving the nutritional value of bakery products and lowering waste generation. [Display omitted] • Dietary fibre from cereals and pseudocereals are important for balanced human diet. • Modification of DF can greatly influence dough processing and product digestibility. • Different types of fermentation are the most used tool for cereal DF modification. • S. cerevisiae and Lactobacillus spp. are predominantly used in dough fermentation. • Combination of different microbe cultures has synergistic modification effect on DF. [ABSTRACT FROM AUTHOR]

Cheese whey is the major by-product of the dairy industry, and its disposal constitutes an environmental concern. The production of cheese whey has been increasing, with 190 million tonnes per year being produced nowadays. Therefore, it is emergent to consider different routes for cheese whey utilization. The great nutritional value of cheese whey turns it into an attractive substrate for biotechnological applications. Currently, cheese whey processing includes a protein fractionating step that originates the permeate, a lactose-reach stream further used for valorisation. In the last decades, yeast fermentation has brought several advances to the search for biorefinery alternatives. From the plethora of value-added products that can be obtained from cheese whey, ethanol is the most extensively explored since it is the alternative biofuel most used worldwide. Thus, this review focuses on the different strategies for ethanol production from cheese whey using yeasts as promising biological systems, including its integration in lignocellulosic biorefineries. These valorisation routes encompass the improvement of the fermentation process as well as metabolic engineering techniques for the introduction of heterologous pathways, resorting mainly to Kluyveromyces sp. and Saccharomyces cerevisiae strains. The solutions and challenges of the several strategies will be unveiled and explored in this review.

Desugarization is an important technique in industrial egg processing to maintain the color and shelf life of egg white powder. Its effect on proteolysis of egg white protein is essential in understanding the functionality changes in the obtained hydrolysate. Two desugarization methods, including yeast fermentation and enzyme desugarization using glucose oxidase are commonly employed in industrial scale egg white processing but the suitable method which can improve egg white protein hydrolysates' functionality has not yet been reported. Thus, the present work compares the physicochemical, functional, and surface properties of egg white protein hydrolysates obtained through both the desugarization methods. Alcalase enzyme (2% w/w) was used for enzyme hydrolysis. The degree of hydrolysis of desugared egg white hydrolysate was higher than the non-desugared samples by 34.5%. The desugared samples (especially yeast fermented) had higher foaming and emulsifying ability than non-desugared samples; however, it showed emulsion activity index and surface hydrophobicity. Compared to native protein, the in-vitro trypsin digestibility of desugared hydrolysate samples was significantly (p

Whey is a dairy residue generated during the production of cheese and yogurt. Whey contains mainly lactose and proteins, contributing to its high chemical oxygen demand (COD). Current environmental regulations request proper whey disposal to avoid environmental pollution. Whey components can be transformed by yeast into ethanol and biomolecules with aroma and flavor properties, for example, 2-phenyethanol (2PE), highly appreciated in the industry due to its organoleptic and biocidal properties. The present study aimed to valorize agri-food residues in 2PE by developing suitable bioprocess. Cheese whey was used as substrate source, whereas crab headshells, residual soy cake, and brewer’s spent yeast (BSY) were used as renewable nitrogen sources for the yeasts Kluyveromyces marxianus and Debaryomyces hansenii. The BSYs promoted the growth of both yeasts and the production of 2PE in flask fermentation. The bioprocess scale-up to 2 L bioreactor allowed for obtaining a 2PE productivity of 0.04 g2PE/L·h, twofold better productivity results compared to the literature. The bioprocess can save a treatment unit because the whey COD decreased under the detection limit of the analytical method, which is lower than environmental requirements. In this way, the bioprocess prevents environmental contamination and contributes to the circular economy of the dairy industry.

The increase in the wastage of bread, representing 12.5 million tons per year, causes ecological problems, such as the production of methane and CO2, when that waste bread (WB) is improperly managed. To reduce this ecological footprint, a more sustainable system of WB management must be set up. Based on its chemical composition, WB has a high potential to be used as feedstock for microbial growth and conversion into value-added bio products. The microbial valorisation of WB is a novel biotechnological approach to upgrading a waste into a renewable feedstock for bio-based industry, thus favouring the circular economy concept. Based on this, the aim of this study was to test WB as a feedstock for biomass production by Yarrowia lipolytica, which can be considered as a promising supplement for animal and human dietary products. The enzymatic hydrolysis of WB was primarily optimized for large-scale production in a bioreactor. The biomass production of Y. lipolytica strain K57 on WB hydrolysate-based media in batch bioreactor culture was then investigated. As a result, a very high starch to glucose conversion yield of 97% was obtained throughout optimised hydrolysis. At the end of 47 h of batch culture, a biomass higher than 62 g/L, specific growth rate of 0.37 h−1 and biomass yield of 0.45 g/g were achieved from a WB hydrolysate. Therefore, this study demonstrates that WB hydrolysate has a promising potential to be used as a feedstock for biomass production by Y. lipolytica strain K57 for food and animal diet applications.

Summary: Desugaring is a necessary step to prevent undesirable attributes of the egg white (EW) products. In this study, the effects of yeast fermentation and glucose oxidase (GOD) method on the functionalities of EW were compared. Yeast fermentation treatment led to the formation of poor EW gel with low hardness due to the porous structure brought by increased foam capacity (FC). In contrast, GOD treatment increased the hardness of EW gel by increasing the surface hydrophobicity (H0) and ordered secondary structure and decreased the foaming capacity and stability of EW by decreasing absolute potential. In addition, the foam structure became more compact after yeast fermentation compared to GOD treatment. However, the water holding capacity (WHC) of both EW gels with desugaring treatments decreased due to the porosity of the internal gel network confirmed by scanning electron microscopy. These results provide a guide for the selection of sugar‐free EW liquid in the subsequent application. [ABSTRACT FROM AUTHOR]

[Display omitted] • Dilute acid pretreatment of corn bran with low temperature (90 °C for 60 min). • High sugar yields (95% for starch, 77% for both cellulose and xylan). • Highly efficient fermentation (100 % glucose and 91 % xylose conversion within 24 h). • The process was scaled up to 150-L. Fractionated corn bran was processed to maximize ethanol production from starch, cellulose, and xylan. After various bench-scale experiments, an optimized process with dilute acid pretreatment (1.5 % w/w H 2 SO 4) at 90 °C for 60 min was utilized followed by enzymatic hydrolysis using cellulase and hemicellulase for 48 hr. After simultaneous saccharification (regarding starch) and fermentation at 150 L using an engineered yeast, which consumes both glucose and xylose to make ethanol, the 86 % total sugar conversion yield was achieved, including conversions of 95 % for starch, 77 % for cellulose and 77 % for xylan. Also, an accurate mass balance was formulated for ethanol-producing carbohydrates including starch, cellulose, and xylan from feedstock to final ethanol. A highly efficient process of converting corn fiber to ethanol was successfully scaled up to 150 L. [ABSTRACT FROM AUTHOR]