Yeast Fermentation Research Articles

Ethanol Production From Sugarcane Molasses: Effects of Ph, Supplementation, and Refrigeration in Simulated Industrial Conditions at a Microdistillary

Objective: This study aims to evaluate the effects of pH, ammonium sulfate supplementation, and refrigeration on fermentation performance in sugarcane molasses, with the goal of optimizing ethanol production under simulated industrial conditions. Theoretical Framework: The research builds on key concepts in biofuel production, emphasizing the role of pH, nutrient supplementation, and temperature control in influencing yeast metabolism and fermentation efficiency. Theories on enzymatic activity and nutrient absorption (Vidal et al., 2013; Gutierrez, 1993) provide the foundation for understanding the interactions between these factors. Method: A full 2³ factorial design was employed, evaluating the effects of pH (3.5 and 5.0), supplementation (0.0 and 1.0 g/L), and refrigeration (with or without) on fermentation efficiency, process efficiency, ethanol productivity, and substrate-to-cell conversion in a microdistillery. Analytical methods included spectrophotometry, refractometry, and chromatography. Results and Discussion: The results indicate that fermentation conditions with pH 3.5, without supplementation, and with refrigeration yielded the best performance, with significant increases in ethanol productivity and fermentation efficiency. The interaction between variables suggests that these factors should be considered jointly to optimize the process. Research Implications: The findings offer practical insights for improving fermentation in industrial biofuel production, particularly in optimizing conditions for ethanol yield and process efficiency under near-industrial conditions. Originality/Value: This study contributes by using a microdistillery to simulate industrial conditions, providing more accurate data for scaling ethanol production. It adds value by highlighting how specific combinations of pH, supplementation, and refrigeration can improve biofuel sustainability.

Engineering a xylose fermenting yeast for lignocellulosic ethanol production.

Lignocellulosic ethanol is produced by yeast fermentation of lignocellulosic hydrolysates generated by chemical pretreatment and enzymatic hydrolysis of plant cell walls. The conversion of xylose into ethanol in hydrolysates containing microbial inhibitors is a major bottleneck in biofuel production. We identified sodium salts as the primary yeast inhibitors, and evolved a Saccharomyces cerevisiae strain overexpressing xylose catabolism genes in xylose or glucose-mixed medium containing sodium salts. The fully evolved yeast strain can efficiently convert xylose in the hydrolysates to ethanol on an industrial scale. We elucidated that the amplification of xylA, XKS1 and pentose phosphate pathway-related genes TAL1, RPE1, TKL1, RKI1, along with mutations in NFS1, TRK1, SSK1, PUF2 and IRA1, are responsible and sufficient for the effective xylose utilization in corn stover hydrolysates containing high sodium salts. Our evolved or reverse-engineered yeast strains enable industrial-scale production of lignocellulosic ethanol and the genetic foundation we uncovered can also facilitate transfer of the phenotype to yeast cell factories producing chemicals beyond ethanol.

Successful combination of lactic acid bacteria and yeast fermentation and enzymatic treatment to re-cycle industrial bread by-products for bread making

Successful combination of lactic acid bacteria and yeast fermentation and enzymatic treatment to re-cycle industrial bread by-products for bread making

Chemical and sensory characteristics of lingonberry (Vaccinium vitis-idaea) alcoholic beverages produced using Saccharomyces cerevisiae, Torulaspora delbrueckii and Metschnikowia pulcherrima yeasts

Even though lingonberry (Vaccinium vitis-idaea) is categorised as a superfruit due to its bioactive composition, its challenging flavour profile leads to difficulty in valorisation. In addition, fermentation of lingonberry is limited due to presence of the antimicrobial benzoic acid. This study employed baker’s yeast mediated benzoic acid decrease, followed by conventional (Saccharomyces cerevisiae) and non-conventional (Torulaspora delbrueckii and Metschnikowia pulcherrima) fermentation to produce alcoholic lingonberry beverages. Profiling of the lingonberry alcoholic beverages was done through characterisation of volatile compounds with GC-MS and of sensory properties with a semi-trained panel. The benzoic acid decrement step was successful in reducing the content from 0.66 g/L to 0.04 g/L. Alcoholic beverages were created with an average alcohol content of 7.34% (±0.26). There were increments in the ester- and alcohol- odours alongside a decrease in the original lingonberry flavour. This was supported by higher contents of esters and higher alcohols along with a decrease of certain terpenes in alcoholic beverages. All alcoholic beverages were perceived as notably sour and thus, only minor differences were observed between the used yeasts. In particular, M. pulcherrima yeast produced a sweeter and less sour alcoholic beverage compared to the original juice. Overall, benzoic acid reduction facilitates in yeast fermentation to improve market potential of the underutilised berry in alcoholic beverage production.

Preparation of safflower fermentation solution and study on its biological activity.

Safflower, a traditional Chinese medicine, is rich in chemical components including flavonoids, polysaccharides, and alkaloids. It exhibits pharmacological effects such as antioxidant, anti-inflammatory, anti-tumor, and anti-thrombosis properties, making it a valuable resource in the medical field. Furthermore, due to its antioxidant and anti-inflammatory effects, safflower is increasingly being utilized in the cosmetics industry. In this study, yeast was employed to ferment safflower, and the optimal fermentation conditions were established through single-factor experiments and response surface methodology. Subsequently, the antioxidant and anti-inflammatory efficacy of the safflower fermentation solution was assessed using both cellular and zebrafish models. Finally, the safety of the safflower fermentation solution was evaluated through a cosmetic eye irritation test. From a total of 20 yeast strains, YF-5 was identified as the dominant strain for safflower fermentation. By optimizing the fermentation conditions, it was established that the optimal parameters for YF-5 fermentation of safflower are as follows: a fermentation temperature of 36.55°C, a material-to-liquid ratio of 1:20.46, a fructose concentration of 6.20%, a fermentation duration of 72 h, and an inoculum volume of 4%. The biological activities of safflower, including its antioxidant and anti-inflammatory properties, were enhanced through yeast fermentation. In HaCaT cell and zebrafish oxidative damage assays, safflower fermentation solution inhibits the production of malondialdehyde (MDA) and increases superoxide dismutase (SOD) activity as well as total antioxidant capacity (T-AOC). In the RAW264.7 cell inflammatory damage assays, a 20% safflower fermentation solution was found to inhibit the release of TNF-α and NO in the inflammatory model, with inhibition rates of 30.94 and 28.86%, respectively. In the zebrafish inflammatory damage assays, the quantity of fluorescent neutral proteins in the 5% safflower fermentation solution was 0.7 times that observed in the dexamethasone (0.1 mg/mL) positive control group, indicating that its anti-inflammatory activity is comparable to that of dexamethasone (0.1 mg/mL). In the chicken embryo chorionic membrane experiment, it was observed that the safflower fermentation solution did not cause significant damage to the blood vessels of the chorionic allantoic membrane (CAM). This finding demonstrates that the safflower fermentation solution possesses a certain degree of safety. Safflower fermentation solution has antioxidant and anti-inflammatory bioactivities, and it has passed cosmetic safety evaluations. It can be used as a new natural cosmetic ingredient added to cosmetic products.

Impact of Natural Phytosanitary Product Residuals on Yeast Fermentation Performance and Wine Composition.

Although phytosanitary treatments are necessary to protect grapes from parasitic diseases, consumers are increasingly concerned about the use of synthetic phytosanitary products and their possible residues in wine. Pre-harvest phytosanitary treatments are often inevitable, and consequently downtime is required to avoid possible residues on the grapes. Instead, natural phytosanitary products, such as essential oil (EO)-based products, can be applied close to the harvest without specific restrictions, with results that are not only technically convenient but also more attractive for the consumers. Because of the high antimicrobial activity of EO products, in the present study we evaluated the effect of different residual amounts of two new EO-based phytosanitary products on the alcoholic fermentation and the chemical composition of the final fermented products. In particular, two EO-based new formulations, exploitable in organic viticulture management, were evaluated. Increasing concentrations of each formulation were tested during laboratory scale fermentations and in comparison with synthetic and natural commercial phytosanitary products. Growth and fermentation kinetics of a commercial yeast strain of Saccharomyces cerevisiae and the chemical and sensory profiles of the final products were evaluated. Both new formulations showed no significant impact on the growth and fermentation kinetic of S. cerevisiae at any of the concentrations tested. In all trials, alcoholic fermentation was completed in 15 days. Instead, a different chemical composition of the final products was observed. Therefore, these new products might represent an interesting alternative tool to the conventional phytosanitary treatments, being applicable close to the harvest without negative impacts on the kinetics of alcoholic fermentation and also being more acceptable to wine consumers.

Distinct effects of dilute acid prehydrolysate inhibitors on enzymatic hydrolysis and yeast fermentation.

The effects of dilute acid prehydrolysate from poplar were investigated and compared in the enzymatic hydrolysis, fermentation, and simultaneous saccharification fermentation (SSF) in this study. The improvement of enzymatic hydrolysis and fermentation with resin adsorption and surfactant addition has also been represented. A total of 16 phenolic alcohols, aldehydes, acids and 3 furan derivatives in the prehydrolysates were identified and quantified by gas chromatography/mass spectrometry (GC/MS). The degree of inhibition from the phenolic compounds (26.55%) in prehydrolysate on the enzymatic hydrolysis was much higher than carbohydrates-derived inhibitors (0.52-4.64%). Around 40% degree of inhibition was eliminated in Avicel enzymatic hydrolysis when 75% of prehydrolysates phenolic compounds were removed by resin adsorption. This showed distinguishing inhibition degrees of various prehydrolysate phenolic compounds. Inhibition of prehydrolysate on enzymatic hydrolysis was more dosage-dependent, while their suppression on the fermentation showed a more complicated mode: fermentation could be terminated by the untreated prehydrolysate, while a small number of prehydrolysate inhibitors even improved the glucose consumption and ethanol production in the fermentation. Correlated with this distinct inhibition modes of prehydrolysate, the improvement of Tween 80 addition in SSF was around 7.10% for the final ethanol yield when the glucose accumulation was promoted by 76.6%.

Evaluating the multifaceted impact of Cephalaria extract on dough quality: Antioxidant, antimicrobial, and cytotoxic properties

SummaryCephalaria syriaca, known as cephalaria, is an annual, pilose plant with pink‐purple flowers growing wild in wheat fields. Viscoelastic properties of gluten‐free doughs can be improved by adding cephalaria. However, this addition results in some undesirable properties in bread such as bitter taste and dark internal colour. This study aimed to reduce these effects by obtaining cephalaria obtained from distilled water and ethanol extracts and to increase the potential use of extracts in bread production. Different proportions of water and ethanol extracts obtained from oil‐free cephalaria were added to bread by creating a model with Mixture Design, and the optimum concentration was determined by farinograph trials. The antioxidative, antimicrobial, and cytotoxic effects of extract and the effect of cephalaria on yeast activity were examined. Cephalaria extracts had no measurable antimicrobial effect and no antifungal effect on Rhizopus stolonifer, while an antifungal effect was found against A. niger and P. expansum. The IC50 value was found to be 4.15 mg mL−1 for ethanol extract while the water extract had no effect on cells. The addition of extract had no negative effect on the number of yeasts in sourdough fermentation. The study has improved the usage of cephalaria by using water and ethanol extracts in dough.

Simultaneous recycling of flavonone and polymethoxyflavonoids from Chenpi processing residue based on their complementary action on glycolipid lowering activity: Innovative combination use of yeast and aqueous two-phase system

This study aimed at recycling flavonoids with glycolipid lowering activity from Chenpi processing residue produced by essential oil extraction. The crude Chenpi flavonoids obtained by ethanol reflux mainly contained flavonone (hesperidin) and polymethoxyflavonoids (nobiletin, tangeretin, sinensetin, and isosinensetin), which complementally exerted strong glycolipid lowering activity as revealed by digestive enzyme inhibitory activity, molecular docking and network pharmacology. The reducing sugar and water-soluble impurities were efficiently removed by yeast fermentation and aqueous two-phase system (ATPS) extraction, respectively. The optimal combination use of yeast (2 % w/v, CN36) and ATPS formed by 22 % (w/w) (NH4)2SO4 and 25 % (w/w) ethanol improved flavonoid purity to 60.25 %, enriched flavonone and polymethoxyflavonoids by 6.69-fold, and enhanced digestive enzyme inhibitory activity, which was superior to the use of individual yeast or ATPS, unoptimized combination, macroporous resin (XAD-16), and ethyl acetate. This study was the first to develop a recyclable biophysical method for simultaneous enrichment of flavonone and polymethoxyflavonoids.

Fabrication of yeast engineered porous 13X adsorbent layers for CO2 capture

This study investigates a novel environmentally friendly coating technique using yeast fermentation to obtain super porous Zeolite 13X adsorbent layers through freeze-drying technique for CO2 capture applications. Several mass ratios of sugar to yeast were used to control the porosity and pore sizes in the adsorbent layer. A unique peeling process was integrated to obtain foamy, hollow structures to have deeper layer accessibility of adsorbent for adsorption applications. These coated adsorbent layers were experimentally characterized as a function of the mass ratio of sugar to yeast and adsorbent solid fraction. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and Fourier-transform infrared spectroscopy (FT-IR) are used to analyze the coated layers. The void fraction for coated samples is found to vary between 0.48 and 0.56, making the samples applicable for adsorption applications. Adsorption performance experiments are performed to test the coated samples' performance compared to 13X powder. Due to their simplistic fabrication, cost-effectiveness, rapid pore formation, and high adsorption capacity, these porous 13X layers hold potential for large-scale fabrication and CO2 capture applications.

The role of starch digestion in the brewing of gluten-free beers

Celiac disease affects an estimated 1% of the global population, and symptoms are triggered by the consumption of gluten in sensitized individuals. Other gluten sensitivities exist but are poorly characterized or often under-diagnosed, leading a number of people to pursue a gluten-free or gluten-reduced diet even in the absence of a diagnosis. Gluten is a complex suite of proteins from the prolamin fraction of storage proteins in barley, wheat, and rye, meaning that foods or beverages that are produced from these cereals will also contain gluten. Beer is one such beverage that is traditionally produced from malted barley and is thus incompatible with a gluten-free lifestyle. The simplest option to produce a gluten-free beer would seem to be to use alternative, gluten-free, grains such as millet, sorghum, teff, rice, corn or other starchy materials. However, barley has thousands of years of development as a brewing agent behind it and these alternative ingredients cannot be incorporated into the brewing process without substantial alterations. Particularly, these ingredients generally have much lower endogenous starch degrading activity and much higher starch gelatinization temperatures as compared to barley which makes generating sufficient fermentable sugars for yeast fermentation a challenge. In this review we will further elucidate these challenges as well as the solutions that are being developed to bring beer to the gluten-free masses.

Pelatihan pembuatan minuman probiotik fermentasi dari limbah kulit nanas (Ananas comosus L.) di Desa Seruawan

Pineapple skin is an ingredient that can be processed into a probiotic drink. The biggest component of pineapple peel waste besides water is carbohydrates. Pineapple skin can be a good substrate as a source of microbial growth. Pineapple skin can reach 47% of the total fruit and has a chemical composition of 87.80% water, 8.60% sugar and 1.35% reducing sugar. The potential chemical content of pineapple skin has encouraged many researchers to create fermented prebiotic drink products. The ingredients used in making pineapple peel fermented probiotic drinks include: pineapple fruit, fermented yeast, water, palm sugar, cinnamon and granulated sugar. This community service activity was carried out with the aim of educating the public about how to make pineapple peel prebiotic drinks for household scale. There is a need for training in making fermented prebiotic drinks from pineapple peel in local communities. This training will be carried out for the community in Seruawan village, Seram Island, Maluku.

Influence of native coffee yeast fermentation on phenolic content, organic acids, and volatile compounds in cascara

Fermentation has been shown to significantly influence the quality of cascara, a functional beverage derived from dried coffee cherry pulp. While native coffee yeasts are acknowledged for their role in modulating the sensory characteristics of coffee, their impact on the quality of cascara has not been systematically investigated. This study successfully isolated 12 aromatic yeast strains from wet coffee fermentation and evaluated their potential as starter cultures for cascara fermentation. The results revealed that a mixed culture of Wickerhamomyces anomalus YN5 and Kazachstania humilis YN9 significantly enhanced the phenolic content and antioxidant activity of cascara by 12.68% and 10.77%, respectively, compared to those of unfermented cascara. Furthermore, cascara fermented with this mixed yeast culture exhibited markedly increased levels of acetic acid, lactic acid, ethanol, linalool, benzyl alcohol, and acetophenone, thereby augmenting its acidity, alcoholic notes, and floral-fruity aroma. These findings suggest that native coffee yeasts can serve as effective starter cultures for improving both the sensory and nutritional quality of cascara beverages.

The structural properties of “Huilou” yam starch fermented with five microbial species

In this study, we employed two lactic acid bacterial species, two yeast species, and Bacillus amyloliquefaciens to ferment “Huilou” yam starch. The aim was to explore the effects of fermentation time and microbial species on the structural properties of yam starch. The results showed that fermentation caused an increase in relative crystallinity (29.23 %–37.98 %) compared with native starch (25.69 %). The fermentation process altered the thermal properties of yam starch, leading to higher enthalpy of gelatinization values compared with unfermented starch. Notably, an absorption peak of native starch shifted from 992 cm−1 to 1015 cm−1 upon 2-day fermentation by Bacillus amyloliquefaciens and 5-day fermentation by Lactobacillus plantarum or Pediococcus pentococcus, associated with an increase in the presence of amorphous structures in yam starch. “Huilou” yam starch obtained through lactic acid bacterial fermentation exhibited a significant presence of organic acids, whereas samples derived from Bacillus amyloliquefaciens fermentation were primarily affected by amylase activity. Following yeast fermentation, organic acids and amylase were observed, albeit with relatively low influence. This research reveals that microbial fermentation can potentially alter the structural characteristics of yam starch, which can improve the quality of yam starch-based foods.

Diversity of Saccharomyces cerevisiae Yeast Strains in Granxa D’Outeiro Winery (DOP Ribeiro, NW Spain): Oenological Potential

Yeasts play an essential role in the aroma and sensory profiles of wines. Spontaneous fermentations were carried out at the newly built winery of Granxa D’Outeiro. Yeasts were isolated from must at different stages of fermentation. Colonies belonging to Saccharomyces cerevisiae were characterised at the strain level by mtDNA-RFLPs. General chemical parameters and aroma profiles of the wines were determined using official OIV methodology and GC-MS analysis, respectively. The diversity of S. cerevisiae per fermentation ranged from 5 to 13 different strains depending on the grapevine variety. Out of 24 strains, strain B was the dominant yeast in most fermentations at different proportions, but strains D, E, and H also reached up to 25% of the total population in some fermentations. The yeast diversity was higher in the Lado fermentation than in those containing Treixadura. The chemical compositions of the wines revealed differences among them, with Loureira and Albariño wines showing the highest content of volatile compounds. The evaluation of their technological properties revealed the oenological potential of some strains of S. cerevisiae. The strains showing the best scores were selected to be used in future vintages to enhance the typicality of wines in the Granxa D’Outeiro winery.

Assessing the physiological properties of baker's yeast based on single-cell Raman spectrum technology

With rapid progress in the yeast fermentation industry, a comprehensive commercial yeast quality assessment approach integrating efficiency, accuracy, sensitivity, and cost-effectiveness is required. In this study, a new yeast quality assessment method based on single-cell Raman technology was developed and contrasted with traditional methods. The findings demonstrated significant associations (Pearson correlation coefficient of 0.933 on average) between the two methods in measuring physiological indicators, including cell viability and intracellular trehalose content, demonstrating the credibility of the Raman method compared to the traditional method. Furthermore, the sensitivity of the Raman method in viable but non-culturable cells was higher in measuring yeast cell viability (17.9 % more sensitive). According to the accurate quantitative analysis of metabolic activity level (MAL) of yeast cells, the cell vitality was accurately quantified at population and single-cell levels, offering a more comprehensive assessment of yeast fermentation performance. Overall, the single-cell Raman method integrates credibility, feasibility, accuracy, and sensitivity in yeast quality assessment, offering a new technological framework for quality assessments of live-cell yeast products.

Investigation of the effect of specific gravity and pH on the fermentation period of a single and combined algae species as a potential bioethanol feedstock

Algae has garnered significant attention as a promising biomass source for bioethanol production and as a solution to sustainability issues. Nevertheless, the disruption of complex carbohydrates required for yeast fermentation occurs during algae cultivation. The fermentation process, which is critical for producing bioethanol as a cost-effective and environmentally friendly alternative fuel, may be improved by meticulously managing the parameters that influence fermentation, such as specific gravity and pH. Bioethanol was produced from algae species (Navicula sp., Oscillatoria sp. and diatoms) using simultaneous saccharification and fermentation (SSF) processes. A control, single and combined algal species were prepared in the following formation: Oscillatoria sp. and Navicula sp. (sample A), Oscillatoria sp. (sample B), diatom and Oscillatoria sp. (sample C), Navicula sp. (sample D), and diatoms, Navicula sp. and Oscillatoria sp (sample E). The daily bioethanol concentrations in the fermentation medium were measured using a digital optical refractometer, and a Two-way ANOVA analysis (p < 0.05) was conducted to determine the differences between the period of fermentation and the bioethanol concentration. Additionally, the pH and specific gravity were assessed. The Two-way ANOVA analysis conducted indicated that the F-values surpassed the F-critical values and the p-values were all notably below 0.05, suggesting a statistically significant distinction between the samples in their fermentation periods and bioethanol concentration. The highest concentration was observed in sample E at 39.53 g/L, followed by samples C and D at 37.36 g/L, samples A and B at 35.10 g/L, and the control at 4.78 g/L. The findings showed that mixed cultures could potentially improve ethanol yield. The optimal fermentation period was determined to be 72 h. The pH levels in the control and algae samples varied between 6.5 and 6.7 and 7.06 to 8.42, respectively. The specific gravity in the control and algae samples ranged from 1.003 to 1.004 and 1.023 to 1.037, respectively. During algae fermentation, specific gravity initially increased, then stabilized before decreasing. pH levels correlated with fermentation duration. Understanding these factors is crucial for maximizing bioethanol production. This discovery could lead to exploring how different algae species interact to improve cultivation methods.

Discovery, Expression, and In Silico Safety Evaluation of Honey Truffle Sweetener, a Sweet Protein Derived from Mattirolomyces terfezioides and Produced by Heterologous Expression in Komagataella phaffii.

Honey truffle sweetener (HTS), a 121 amino acid protein is identified as a high-intensity sweetener found naturally occurring in the Hungarian Sweet Truffle Mattirolomyces terfezioides, an edible mushroom used in regional diets. The protein is intensely sweet, but the truffle is difficult to cultivate; therefore, the protein was systematically characterized, and the gene coding for the protein was expressed in a commonly used host yeast Komagataella phaffii. The heterologously expressed protein maintained the structural characteristics and sweet taste of the truffle. Preliminary safety evaluations for use as a food ingredient were performed on the protein including digestibility and in silico approaches for predicting the allergenicity and toxicity of the protein. HTS is predicted to be nonallergenic, nontoxic, and readily digestible. This protein is readily produced by precision fermentation of the host yeast, making it a potential replacement for both added sugars and small molecule high-intensity sweeteners in food.

Identification of genes associated with the high-temperature fermentation trait in the Saccharomyces cerevisiae natural isolate BCC39850.

The fermentative model yeast Saccharomyces cerevisiae has been extensively used to study the genetic basis of stress response and homeostasis. In this study, we performed quantitative trait loci (QTL) analysis of the high-temperature fermentation trait of the progeny from the mating of the S. cerevisiae natural isolate BCC39850 (haploid#17) and the laboratory strain CEN.PK2-1C. A single QTL on chromosome X was identified, encompassing six candidate genes (GEA1, PTK2, NTA1, NPA3, IRT1, and IML1). The functions of these candidates were tested by reverse genetic experiments. Deletion mutants of PTK2, NTA1, and IML1 showed growth defects at 42°C. The PTK2 knock-out mutant also showed significantly reduced ethanol production and plasma membrane H+ ATPase activity and increased sensitivity to acetic acid, ethanol, amphotericin B (AMB), and β-1,3-glucanase treatment. The CRISPR-Cas9 system was used to construct knock-in mutants by replacement of PTK2, NTA1, IML1, and NPA3 genes with BCC39850 alleles. The PTK2 and NTA1 knock-in mutants showed increased growth and ethanol production titers at 42°C. These findings suggest an important role for the PTK2 serine/threonine protein kinase in regulating plasma membrane H+ ATPase activity and the NTA1 N-terminal amidase in protein degradation via the ubiquitin-proteasome system machinery, which affects tolerance to heat stress in S. cerevisiae.

Impact of &lt;i&gt;Pediococcus parvulus&lt;/i&gt; and &lt;i&gt;Saccharomyces cerevisiae&lt;/i&gt; on &lt;i&gt;Brettanomyces bruxellensis&lt;/i&gt; mousy compound production

The presence of mousy off-flavours in wine, attributed to the production of N-heterocycles by lactic acid bacteria or Brettanomyces bruxellensis, poses a significant challenge in the winemaking industry. This study is the first one to investigate the impact of co-cultures focusing on B. bruxellensis with two common wine microorganisms, Pediococcus parvulus and Saccharomyces cerevisiae on the formation of mousy compounds. The screening was conducted in a synthetic medium under controlled conditions. It reveals the nuanced effects of the microorganism combinations. Depending on the P. parvulus or S. cerevisiae strain co-inoculated with B. bruxellensis a synergistic effect is observed on the 2-acetyltetrahydropyridine (ATHP) production, while an inhibitory effect on 2-acetylpyrroline (APY) production by P. parvulus is highlighted when co-inoculated with B. bruxellensis. These findings shed light on the potential impact of the alcoholic fermentation yeast (S. cerevisiae) on the production of mousy off-flavours. Finally, a correlation between ATHP and 2-ethyltetrahydropyridine (ETHP) appears to be confirmed with a ratio of 1:10 between ETHP and ATHP produced in the N-heterocycles assay medium.