Yeast Production Research Articles

Comparative responses of flocculating and nonflocculating yeasts to cell density and chemical stress in lactic acid fermentation.

While flocculation has demonstrated its efficacy in enhancing yeast robustness and ethanol production, its potential application for lactic acid fermentation remains largely unexplored. Our study examined the differences between flocculating and nonflocculating Saccharomyces cerevisiae strains in terms of their metabolic dynamics when incorporating an exogenous lactic acid pathway, across varying cell densities and in the presence of lignocellulose-derived byproducts. Comparative gene expression profiles revealed that cultivating a nonflocculant strain at higher cell density yielded a substantial upregulation of genes associated with glycolysis, energy metabolism, and other key pathways, resulting in elevated levels of fermentation products. Meanwhile, the flocculating strain displayed an inherent ability to sustain high glycolytic activity regardless of the cell density. Moreover, our investigation revealed a significant reduction in glycolytic activity under chemical stress, potentially attributable to diminished ATP supply during the energy investment phase. Conversely, the formation of flocs in the flocculating strain conferred protection against toxic chemicals present in the medium, fostering more stable lactic acid production levels. Additionally, the distinct flocculation traits observed between the two examined strains may be attributed to variations in the nucleotide sequences of the flocculin genes and their regulators. This study uncovers the potential of flocculation for enhanced lactic acid production in yeast, offering insights into metabolic mechanisms and potential gene targets for strain improvement.

Bridging the Implementation Gap between Pomace Waste and Large-Scale Baker’s Yeast Production

The objectives set in the European Green Deal constitute the starting point of this review, which then focuses on the current implementation gap between agro-industrial wastes as resources for large-scale bioprocesses (e.g., baker’s yeast, bioethanol, citric acid, and amino acids). This review highlights the current lack of sustainability of the post-harvest processing of grapes and apples. In light of the European Green Deal, industrial biotechnology often lacks sustainability as well. We reviewed the recent progress reported in the literature to enhance the valorization of grape and apple pomace and the current failure to implement this research in technical processes. Nevertheless, selected recent papers show new perspectives to bridge this gap by establishing close collaborations between academic teams and industrial partners. As a final outcome, for the first time, we drew a circular flow diagram that connects agriculture post-harvest transformation with the industrial biotechnology and other industries through the substantial valorization of apple and grape pomace into renewable energy (solid biofuels) and sugar extracts as feedstock for large-scale bioprocesses (production of baker’s yeast industry, citric acid, bioethanol and amino acids). Finally, we discussed the requirements needed to achieve the successful bridging of the implementation gap between academic research and industrial innovation.

Safety evaluation of the food enzyme leucyl aminopeptidase from non-genetically modified Aspergillus oryzae strain NZYM-EX.

The food enzyme leucyl aminopeptidase (EC 3.4.11.1) is produced with the non-genetically modified microorganism Aspergillus oryzae strain NZYM-EX by Novozymes A/S. The food enzyme is free from viable cells of the production organism. It is intended to be used in eight food manufacturing processes: processing of dairy products for the production of (1) flavouring preparations, (2) modified milk proteins; processing of plant- and fungal-derived products for the production of (3) protein hydrolysates, (4) soy sauce; processing of meat and fish products for the production of (5) protein hydrolysates; processing of cereals and other grains for the production of (6) baked products, (7) brewed products; (8) processing of yeast and yeast products. Dietary exposure to the food enzyme total organic solids (TOS) was estimated to be up to 0.577 mg TOS/kg body weight (bw) per day in European populations. Genotoxicity tests did not indicate a safety concern. The systemic toxicity was assessed by means of a repeated dose 90-day oral toxicity study in rats. The Panel identified a no observed adverse effect level of 440 mg TOS/kg bw per day, the highest dose tested, which, when compared with the estimated dietary exposure, resulted in a margin of exposure of at least 763. A search for similarity of the amino acid sequence of the food enzyme to known allergens was made and no match was found. The Panel considered that the risk of allergic reactions by dietary exposure cannot be excluded, but the likelihood is low. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.

Species identification and strain discrimination of fermentation yeasts Saccharomyces cerevisiae and Saccharomyces uvarum using Raman spectroscopy and convolutional neural networks.

The use of S. cerevisiae and S. uvarum yeast starter cultures is a common practice in the alcoholic beverage fermentation industry. As yeast strains from different or the same species have variable fermentation properties, rapid and reliable typing of yeast strains plays an important role in the final quality of the product. In this study, Raman spectroscopy combined with CNN achieved accurate identification of S. cerevisiae and S. uvarum isolates at both the species and strain levels in a rapid, non-destructive, and easy-to-operate manner. This approach can be utilized to test the identity of commercialized dry yeast products and to monitor the diversity of yeast strains during fermentation. It provides great benefits as a high-throughput screening method for agri-food and the alcoholic beverage fermentation industry. This proposed method has the potential to be a powerful tool to discriminate S. cerevisiae and S. uvarum strains in taxonomic, ecological studies and fermentation applications.

Selection of the most suitable pretreatment method by PROMETHEE for baker's yeast production wastewater in Microbial Fuel Cell

AbstractBACKGROUNDThe high organic load and low biodegradability of the effluent from baker's yeast production limit its use as a substrate in microbial fuel cell (MFC) systems. In this study, baker's yeast production wastewater was used as a substrate in the anode chamber to assess the impact of various pretreatment methods [dilution, microwave (MW), acidic‐thermal, basic‐thermal and ultrasound (US)] on electricity generation and waste treatment. Additionally, azo dye was used as an electron acceptor at the cathode. Power density and coulomb efficiency were evaluated for electricity generation, and chemical oxygen demand (COD) removal and azo dye removal parameters were evaluated for treatability.RESULTSThe maximum power densities obtained were 83.53, 46.54, 19.41, 67.40, 41 and 33 mW m−2 for MW, acidic thermal, alkaline‐thermal and US pretreatments, diluted raw and raw wastewater, respectively. To determine the most suitable pretreatment method, PROMETHEE was performed using the criteria of maximum power density, COD removal, azo dye removal, coulombic efficiency and pretreatment cost. The most suitable method was found to be MW pretreatment. The order of the alternatives was found to be MW > US > acidic/thermal > diluted raw > raw > alkaline/thermal. With the MW pretreatment, 81.34% azo dye removal, 5 g L−1 COD removal, 0.27% coulombic efficiency and €0.284 L−1 pretreatment cost were obtained.CONCLUSIONThe most suitable pretreatment method to be applied to wastewater for the treatment of baker's yeast production wastewater and high energy production was determined as MW using the PROMETHEE approach. © 2023 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).

The Effect of Dietary Supplementation with Probiotic and Postbiotic Yeast Products on Ewes Milk Performance and Immune Oxidative Status.

The administration of yeast products as feed additives has been proven to beneficially affect animal productivity through energy, oxidative, and immune status improvement. This study evaluated a combination of Saccharomyces cerevisiae live yeast (LY) with yeast postbiotics (rich in mannan-oligosaccharides (MOS) and beta-glucans) and selenium (Se)-enriched yeast on ewes' milk performance and milk quality, energy and oxidative status, and gene expression related to their immune system during the peripartum period. Ewes were fed a basal diet (BD; F:C = 58:42 prepartum and 41:59 postpartum) including inorganic Se (CON; n = 27), the BD supplemented with a LY product, and inorganic Se (AC; n = 29), as well as the combination of the LY, a product of yeast fraction rich in MOS and beta-glucans, and organic-Se-enriched yeast (ACMAN; n = 26) from 6 weeks prepartum to 6 weeks postpartum. The β-hydroxybutyric acid concentration in the blood of AC and ACMAN ewes was lower (compared to the CON) in both pre- and postpartum periods (p < 0.010). Postpartum, milk yield was increased in the AC and ACMAN Lacaune ewes (p = 0.001). In addition, the activity of superoxide dismutase (p = 0.037) and total antioxidant capacity (p = 0.034) measured via the 2,2-Azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) method was increased in the blood plasma of the ACMAN postpartum. Higher ABTS values were also found (p = 0.021), while protein carbonyls were reduced (p = 0.023) in the milk of the treated groups. The relative transcript levels of CCL5 and IL6 were downregulated in the monocytes (p = 0.007 and p = 0.026 respectively), and those of NFKB were downregulated in the neutrophils of the ACMAN-fed ewes postpartum (p = 0.020). The dietary supplementation of ewes with yeast postbiotics rich in MOS and beta-glucans, and organic Se, improved energy status, milk yield and some milk constituents, and oxidative status, with simultaneous suppression of mRNA levels of proinflammatory genes during the peripartum period.

Production of high protein yeast using enzymatically liquefied almond hulls

Animal feed ingredients, especially those abundant in high quality protein, are the most expensive component of livestock production. Sustainable alternative feedstocks may be sourced from abundant, low value agricultural byproducts. California almond production generates nearly 3 Mtons of biomass per year with about 50% in the form of hulls. Almond hulls are a low-value byproduct currently used primarily for animal feed for dairy cattle. However, the protein and essential amino acid content are low, at ~30% d.b.. The purpose of this study was to improve the protein content and quality using yeast. To achieve this, the almond hulls were liquefied to liberate soluble and structural sugars. A multi-phase screening approach was used to identify yeasts that can consume a large proportion of the sugars in almond hulls while accumulating high concentrations of amino acids essential for livestock feed. Compositional analysis showed that almond hulls are rich in polygalacturonic acid (pectin) and soluble sucrose. A pectinase-assisted process was optimized to liquefy and release soluble sugars from almond hulls. The resulting almond hull slurry containing solubilized sugars was subsequently used to grow high-protein yeasts that could consume nutrients in almond hulls while accumulating high concentrations of high-quality protein rich in essential amino acids needed for livestock feed, yielding a process that would produce 72 mg protein/g almond hull. Further work is needed to achieve conversion of galacturonic acid to yeast cell biomass.

PSVIII-13 Evaluating the Effects of a Dried brewer’s Yeast Product on the Fecal Characteristics, Metabolites, and Microbiota Populations of Adult Dogs

Abstract Inclusion of brewer’s yeast in pet foods has become popular because of the potential health benefits it provides. However, more research is needed to evaluate the effects of different brewer’s yeast products on canine gut health outcomes. This study aimed to investigate the effects of a brewer’s yeast product on the fecal characteristics, metabolites, and microbiota populations of adult dogs. Sixteen healthy adult dogs (BW: 9.0 ± 1.7 kg) were acclimated for 7 days and then randomly assigned to a control diet containing no yeast or a brewer’s yeast-containing diet (n = 8/group) for a 21-day period. Fresh fecal samples were collected before and after treatment for measurement of fecal scores, pH, dry matter content, metabolite concentrations [short-chain fatty acids (SCFA), branched-chain fatty acids (BCFA), ammonia, phenols, indoles], and microbiota populations. All data were analyzed as a percent change from baseline using the PROC MIXED procedure of SAS, with treatment as the main effect and dog as a random effect. Significance was declared at P ≤ 0.05, and trends reported if 0.05 &amp;lt; P ≤ 0.10. The brewer’s yeast treatment tended to increase (P = 0.10) fecal butyrate concentrations more than that of controls, but fecal characteristics (pH; dry matter; fecal scores) and other metabolite concentrations were not affected by treatment. Fecal bacterial alpha diversity metrics were not affected by treatment, but beta diversity analysis (unweighted UniFrac distances) tended (P = 0.09) to show a shift between treatments. Change in relative abundance of fecal Blautia was less (P = 0.05) in dogs fed brewer’s yeast than controls, but other bacterial genera were unaffected by diet. In conclusion, this study suggests that the dried brewer's yeast products tested had little impact on fecal characteristics, metabolites, or microbiota populations of adult dogs. The tendency of greater fecal butyrate concentrations in dogs fed brewer’s yeast is encouraging, but further research is needed to identify the potential health benefits of these products in canine diets.

PSIX-11 Testing the Anti-Inflammatory Effects of brewer’s Yeast Extract on Macrophage Cell Lines in Vitro

Abstract Recent studies have demonstrated that brewer’s yeast may modulate gastrointestinal and immune health. Yeasthas been reported to contain bioactive components that possess anti-inflammatory properties in vitro and in animal models, but source of yeast and processing conditions are unique to each product and require testing. The objective of this study was to evaluate the anti-inflammatory effects of a novel brewer’s yeast product in response to a lipopolysaccharide (LPS) challenge using two macrophage cell lines (Raw 264.7 cells; J774A.1 cells) in vitro. Once cells were stable, they were exposed to one of the following treatments for 24 h: sterile phosphate-buffered saline (placebo), brewer’s yeast extract (low dose or high dose), LPS only (positive control), and LPS + brewer’s yeast extract (low dose or high dose). Quantitative real time PCR (qPCR) was used to analyze relative mRNA production of pro-inflammatory cytokines (IL-6, TNF-α, IL-1α and IL-1β) in response to the treatments. Statistical analysis was performed using the PROC MIXED procedure of SAS, testing for the main effect of treatment. Significance was declared as P ≤ 0.05. As expected, LPS increased expression of IL-6, TNF-α, IL-1α and IL-1β to greater (P &amp;lt; 0.05) concentrations than that of the placebo and yeast treatments in both cell lines. The results also showed that brewer’s yeast treatment in RAW 264.7 cells led to greater (P ≤ 0.01) mRNA expression of IL-6, IL-1α and IL-1β during LPS challenge compared with control (LPS only) cells. In J774A.1 cells, brewer’s yeast treatments reduced (P ≤ 0.01) the mRNA expression of IL-1α and IL-1β during LPS challenge in a dose-dependent manner. However, no differences were observed in the mRNA abundance of TNF-α or IL-6 in J774A.1 cells. These findings suggest that the brewer’s yeast extract tested may possess anti-inflammatory effects in macrophage cell lines in vitro, although the responses varied across cell lines and yeast extract concentrations. Further research is needed to explore the potential applications of brewer’s yeast as an anti-inflammatory agent in the target animals of interest.

Serine Improves Lactic Acid Stress Tolerance and Ethanol Production in Zygosaccharomyces bailii in Baijiu Fermentation.

Lactic acid is the primary inhibitor of the growth and ethanol production of yeasts in Baijiu fermentation. Certain amino acids have been found to be related to stress tolerance in yeasts. This study explored the effect of lactic acid stress on the ethanol-producing yeast Zygosaccharomyces bailii and evaluated the ability of serine to increase the lactic acid tolerance of Z. bailii in vitro. Serine significantly improved Z. bailii viability by 16.5% and ethanol production by 226.6% under lactic acid stress. Under lactic acid stress, serine supplementation led to an increase of 41.9% in cell wall integrity, 31.9% in cell membrane integrity, 296.6% in intracellular adenosine triphosphate (ATP), and 18.4% in the mitochondrial membrane potential. Finally, field emission scanning electron microscopy (FESEM) indicated that serine supplementation maintained the cell shape and reduced cell leakage. This study revealed a novel lactic acid tolerance mechanism of core functional yeasts during Jiang-flavor Baijiu fermentation.

349 Effects of Adding a Yeast Blend to Diets with High Levels of Dried Distillers Grains on Feeding Behavior, Intake, and Performance of Beef Cattle Fattened in Feedlot

Abstract Feeding ruminants with a blend of autolyzed yeast grown on sugarcane molasses and live yeast allows nutritionists to explore synergistic effects on digestion and performance (Angulo et al.,2021; Zapata et al., 2021). However, the feeding behavior and the challenges faced in large pen feedlot operations differ from the behavior and challenges faced by animals studied in small groups or metabolic cages. Therefore, we aimed to study the feeding behavior and performance of beef cattle fed in groups in large pens, mimicking the feedlot operations of leading producers and exports of meat in the world. The trial lasted 112 days and was conducted in Nutripura’s research center in the midwest of Brazil. Six hundred five non-castrated males (Nelore and F1 Nelore-Angus), 405 kg (± 35), distributed in 20 pens, were divided into two treatments: 1) Control, a diet with no yeast additives; 2) Yeast Blend (YB), a diet with a blend of autolyzed yeast and live yeast, SymbioYeast, 7g/anima/day (ICC, São Paulo, Brazil). Both diets contained monesin (28 mg/kg DM). The data were analyzed in the software SAS following the model Yijk= μ+Ti + Fj + Bk +еijk (μ = general mean; T = treatment effect; F = Breed effect; B = backgrounding phase effect; e = error). Initial body weight was used as a covariable to analyze final body weight and average daily gain (ADG). Dry matter intake increased (P &amp;lt; 0,05) when animals were supplemented with YB (10,99kg vs. 11,12kg). Final body weight and hot carcass weight tended (0.1 &amp;gt; P ≥ 0.05) to increase when YB was added to the diet. (598 kg vs. 602 kg, 343 kg vs. 345 kg). The ADG was unaffected (P = 0.1069, control 1.735 kg, and YB 1.768 kg). Increasing DMI is a well now property of some yeast derivatives (Torres et al., 2022). This may be related to changes in digestion (Torres et al., 2022) and the diet’s palatability. The palatability of yeast products is claimed on organoleptic and flavor characteristics (Tao et al., 2023). Drone photos taken every 15 minutes suggested that YB altered how animals interact with feed. Feed was delivered between 0700 h and -0930 h and 1300 h and 1530 h. After delivery, a greater percentage of the visit of the animals to the feed bunkers in YB groups. This behavior was even more evident in the morning feed delivery (Figure 1). In summary, YB increased intake and performance. It also changed the interest of animals in visiting feed bunk.

Potential of Pseudomonas putida probiotic feed mixture for improving growth, immune response, and disease resistance in Nile Tilapia compared to Saccharomyces cerevisiae probiotic

AbstractObjectiveThis study aimed to assess the effects of a potential probiotic feed mixture containing Pseudomonas putida, in comparison to a yeast product (Saccharomyces cerevisiae), on the growth, immune response, and protection against Aeromonas hydrophila infection in Nile Tilapia Oreochromis niloticus.MethodsNile Tilapia were divided into three groups and subjected to a 60‐day feeding regimen: the first group served as a control, receiving a commercial diet; the second group received a basal diet mixed with 1 × 107 CFU/g diet of P. putida; and the third group was fed a basal diet mixed with 1 g/kg diet of dried S. cerevisiae, resulting in a final concentration of 107 CFU/g of feeds. After 2 months of supplementation, various parameters including survival rate, body weight gain, feed conversion rate, specific growth rate, serum lysozyme activity, phagocytic activity, nitroblue tetrazolium activity, and disease resistance against A. hydrophila were evaluated.ResultBoth probiotic‐treated groups exhibited significant improvements compared to the control group. Specifically, enhanced survival rates, body weight gains, feed conversion rates, and specific growth rates were observed in the probiotic‐treated groups. Moreover, these groups demonstrated increased serum lysozyme, phagocytic, and nitroblue tetrazolium activities, indicative of an improved immune response. Notably, the probiotic‐treated groups displayed enhanced resistance against A. hydrophila infection. Histopathological examination revealed that P. putida significantly augmented the nonspecific immune response in Nile Tilapia.ConclusionThis preliminary study underscores the potential benefits of P. putida supplementation in Nile Tilapia diets. The inclusion of P. putida resulted in enhanced growth performance, improved immune status, and effective control of A. hydrophila infection. These findings suggest that P. putida holds promise as a valuable component in feed mixtures for promoting the growth and health of Nile Tilapia.

Safety evaluation of the food enzyme bacillolysin from the non-genetically modified Bacillus amyloliquefaciens strain AGS 430.

The food enzyme bacillolysin (EC 3.4.24.28) is produced with the non-genetically modified Bacillus amyloliquefaciens strain AGS 430 by Kerry Ingredients & Flavours Ltd. The production strain qualifies for the qualified presumption of safety (QPS) approach to safety assessment. The food enzyme is intended to be used in 11 food manufacturing processes: processing of cereals and other grains for the production of baked products; cereal-based products other than baked; brewed products; starch and gluten fractions; distilled alcohol; processing of dairy products for the production of flavouring preparations and modified milk proteins; processing of meat and fish products for the production of protein hydrolysates; processing of plant- and fungal-derived products for the production of protein hydrolysates and plant-based analogues of milk and milk products; processing of yeast and yeast products. Since residual amounts of the total organic solids (TOS) are removed during two processes, dietary exposure was estimated only for the remaining nine food manufacturing processes. Exposure was estimated up to 3.482 mg TOS/kg body weight (bw) per day in European populations. As the production strain qualifies for the QPS approach and no issue of concern arose from the production process of the food enzyme, the Panel considered that no toxicological studies other than the assessment of allergenicity were necessary. A search for the similarity of the amino acid sequence of the food enzyme to known allergens was made and no match was found. The Panel considered that the risk of allergic reactions upon dietary exposure cannot be excluded (except for distilled alcohol production), but the likelihood is low. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.

Safety evaluation of the food enzyme subtilisin from the non-genetically modified Bacillus licheniformis strain NZYM-CX.

The food enzyme subtilisin (EC 3.4.21.62) is produced with the non-genetically modified Bacillus licheniformis strain NZYM-CX by Novozymes A/S. The production strain met the requirements for the qualified presumption of safety (QPS) approach. The food enzyme is intended to be used in eight food manufacturing processes: processing of cereals and other grains for the production of brewed products; processing of dairy products for the production of modified milk proteins and flavouring preparations; processing of plant- and fungal-derived products for the production of plant-based analogues of milk and milk products, protein hydrolysates and edible oils from algae; processing of meat and fish products for the production of protein hydrolysates; processing of yeast and yeast products. Since residual amounts of total organic solids (TOS) are removed in the production of edible oils from algae, dietary exposure was calculated only for the remaining seven food manufacturing processes. Exposure was estimated to be up to 2.393 mg TOS/kg body weight (bw) per day in European populations. As the production strain qualified for the QPS approach and no issues of concern arose from the production process of the food enzyme, the Panel considered that toxicological studies were unnecessary. A search for the similarity of the amino acid sequence of the food enzyme to known allergens was performed, and a total of 20 matches were found, 17 to respiratory allergens, two to food allergens (found in muskmelon and pomegranate) and one to a contact allergen. The Panel considered that the risk of allergic reactions upon dietary exposure to this food enzyme cannot be excluded, especially in individuals sensitised to muskmelon or pomegranate, but would not exceed the risk of consuming these foods. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.

Safety evaluation of the food enzyme bacillolysin from the non-genetically modified Bacillus amyloliquefaciens strain HPN 131.

The food enzyme bacillolysin (EC 3.4.24.28) is produced with the non-genetically modified Bacillus amyloliquefaciens strain HPN 131 by ENMEX SA de CV. The production strain qualifies for the qualified presumption of safety (QPS) approach to safety assessment. The food enzyme under assessment is intended to be used in seven food manufacturing processes: processing of cereals and other grains for the production of baked products, brewed products and distilled alcohol; processing of dairy products for the production of modified milk proteins; processing of meat and fish products for the production of protein hydrolysates; processing of plant- and fungal-derived products for the production of protein hydrolysates; processing of yeasts and yeast products. Since residual amounts of total organic solids (TOS) are not carried over to distilled alcohol, a dietary exposure was estimated only for the remaining six food manufacturing processes. Exposure was estimated to be up to 8.302 mg TOS/kg body weight (bw) per day in European populations. As the production strain qualifies for the QPS status and no issue of concern arose from the production process of the food enzyme, the Panel considered that no toxicological studies other than the assessment of allergenicity were necessary. A search for the similarity of the amino acid sequence of the food enzyme to known allergens was made and no matches were found. The Panel considered that the risk of allergic reactions by dietary exposure cannot be excluded (except for distilled alcohol production), but the likelihood is low. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.

Safety evaluation of the food enzyme endo-1,4-β-xylanase from the non-genetically modified Trichoderma citrinoviride strain 278.

The food enzyme endo-1,4-β-xylanase (4-β-d-xylan xylanohydrolase; EC 3.2.1.8) is produced with the non-genetically modified Trichoderma citrinoviride strain 278 by Kerry Ingredients & Flavours Ltd. The food enzyme was considered free from viable cells of the production organism. It is intended to be used in eight food manufacturing processes: processing of cereals and other grains for the production of baked products; production of cereal-based products other than baked, brewed products, starch and gluten fractions, distilled alcohol; processing of fruits and vegetables for the production of juices, wine and wine vinegar and processing of yeast and yeast products. Since residual amounts of total organic solids (TOS) are removed during two processes, dietary exposure was only calculated for the remaining six food manufacturing processes. Exposure was estimated to be up to 4.808 mg TOS/kg body weight (bw) per day in European populations. The Panel was unable to reach a conclusion on genotoxicity and systemic toxicity. A search for the similarity of the amino acid sequence of the food enzyme to known allergens was made and no match was found. The Panel considered that a risk of allergic reactions upon dietary exposure cannot be excluded (except for distilled alcohol production), but the likelihood is low. In the absence of an acceptable full set of toxicological data, the Panel was unable to complete the safety assessment of the food enzyme.

PSI-A-4 The Effects of a Novel Brewer’s Yeast Product on Ruminal Fiber Fermentation in Vitro

Abstract The objective was to evaluate a novel brewer’s yeast product on ruminal fiber fermentation in vitro. The experiment was a completely randomized design and included 4 treatments. Treatments included a negative control (NCON), a commercial brewer’s yeast product (Emprove MX; EMX), and a prototype concentrated brewer’s yeast (T1R8) fed at low and high inclusions (T1R8-L and T1R8-H, respectively). Inclusions for low and high treatments were 0.0008 and 0.0015 g, respectively, to correspond with 7 and 14 g inclusion in a lactating cow diet. Treatments were evaluated in duplicate flasks in 2 replicated runs for a total of four observations per treatment. Flasks contained 2.5 grams dry matter (DM) of substrate to represent a lactating cow diet (30% haylage, 25% corn silage, 20% corn, 15% canola meal, and 10% soybean hulls), and 150mL of rumen fluid mixture (2 McDougall’s buffer:1 rumen fluid ratio). Four F57 sealed Ankom bags were filled with 0.25 grams DM of substrate each to facilitate measuring in vitro DM and neutral detergent fiber disappearance (IVDMD and IVNDFD, respectively). Flasks were incubated at 39°C for 30 hours with sample aliquots collected at hour 0, 8, 16, and 30 to determine pH and volatile fatty acids (VFA). Data were analyzed using the MIXED procedure of SAS 9.4 with IVDMD and IVNDFD considered a main effect of treatment while pH and VFA were analyzed with effects of treatment, time, and their interaction. No differences in IVDMD were observed (P = 0.31) among treatments. Treatment affected (P = 0.01) IVNDFD with EMX (50.6%), T1R8-L (48.6%), and T1R8-H (50.3%) being greater than NCON (45.7%). A treatment by hour interaction (P &amp;lt; 0.01) was observed for total VFA concentration; EMX (71.8 mM), T1R8-L (72.6 mM), and T1R8-H (66.0 mM) were greater than NCON (47.8 mM) at h 8, but all treatments were not different at h 16. A treatment by hour interaction (P &amp;lt; 0.01) was also observed for acetate and propionate; EMX, T1R8-H, and T1R8-L were greater than NCON at h 8, but all treatments were not different at h 16. At h 30, greater propionate was observed for T1R8-H compared with all treatments. No effects of treatment or treatment by hour (P ≥ 0.89) were observed for acetate:propionate ratio. Although a treatment by hour interaction was not observed for pH (P = 0.12), a treatment effect (P = 0.03) indicated T1R8-L was the greatest with EMX being intermediate, and NCON and T1R8-H being the least. Novel brewer’s yeast product T1R8 increased the rate of substrate fermentation in the initial 8 h and increased the extent of fiber degradation after a 30 h in vitro fermentation.

Effective protective agents against organ toxicity of deoxynivalenol and their detoxification mechanisms: A review

Deoxynivalenol (DON) is one of the most prevalent mycotoxins in feed, which causes organ toxicity in animals. Therefore, reducing DON-induced organ toxicity can now be accomplished effectively using protective agents. This review provides an overview of multiple studies on a wide range of protective agents and their molecular mechanisms against DON organ toxicity. Protective agents include plant extracts, yeast products, bacteria, peptides, enzymes, H2, oligosaccharides, amino acids, adsorbents, vitamins and selenium. Among these, biological detoxification of DON using microorganisms to reduce the toxicity of DON without affecting the growth performance of pigs may be the most promising detoxification strategy. This paper also evaluates future developments related to DON detoxification and discusses the detoxification role and application potential of protective agents. This paper provides new perspectives for future research and development of safe and effective feed additives.

Innocell Bioreactor: An Open-Source Development to Produce Biomaterials for Food and Packaging Based on Fermentation Processes

A growing number of science and design scholars and design practitioners have recently embarked on studying fermentation processes to produce alternative materials. The main driver of this trend is the search for a sustainable future by proposing novel alternatives that could substitute or integrate into society’s current production and consumption models. This study presents the development of an open-source bioreactor capable of enhancing and optimizing a symbiotic culture of bacteria and yeast (SCOBY) production process. The bioreactor is part of a greater design-driven project aiming to process edible and non-edible materials. The study presents the experiments and methods that led to the development and refinement of the current bioreactor, and all the information needed to replicate it with tools and equipment currently available under the Creative Commons status. The aim of sharing open-source methods and results to reproduce the bioreactor is to support different interdisciplinary teams of scientists and designers in generating high amounts of SCOBY, accelerating R&amp;D with this auspicious yet underexplored source of bacterial cellulose.

Systematic sequence engineering enhances the induction strength of the glucose-regulated GTH1 promoter of Komagataella phaffii.

The promoter of the high-affinity glucose transporter Gth1 (PGTH1) is tightly repressed on glucose and glycerol surplus, and strongly induced in glucose-limitation, thus enabling regulated methanol-free production processes in the yeast production host Komagataella phaffii. To further improve this promoter, an intertwined approach of nucleotide diversification through random and rational engineering was pursued. Random mutagenesis and fluorescence activated cell sorting of PGTH1yielded five variants with enhanced induction strength. Reverse engineering of individual point mutations found in the improved variants identified two single point mutations with synergistic action. Sequential deletions revealed the key promoter segments for induction and repression properties, respectively. Combination of the single point mutations and the amplification of key promoter segments led to a library of novel promoter variants with up to 3-fold higher activity. Unexpectedly, the effect of gaining or losing a certain transcription factor binding site (TFBS) was highly dependent on its context within the promoter. Finally, the applicability of the novel promoter variants for biotechnological production was proven for the secretion of different recombinant model proteins in fed batch cultivation, where they clearly outperformed their ancestors. In addition to advancing the toolbox for recombinant protein production and metabolic engineering of K. phaffii, we discovered single nucleotide positions and correspondingly affected TFBS that distinguish between glycerol- and glucose-mediated repression of the native promoter.