Gaseous environments modify physiology in the brewing yeastSaccharomyces cerevisiaeduring batch alcoholic fermentation

Abstract

Aims: To investigate the impact of different gaseous atmospheres on different physiological parameters in the brewing yeast Saccharomyces cerevisiae BRAS291 during batch fermentation. Methods and Results: Yeasts were cultivated on a defined medium with a continuous sparging of hydrogen, helium and oxygen or without gas, permitting to obtain three values of external redox. High differences were observed concerning viable cell number, size and metabolites produced during the cultures. The ethanol yields were diminished whereas glycerol, succinate, acetoin, acetate and acetaldehyde yields were enhanced significantly. Moreover, we observed major changes in the intracellular NADH/NAD+ and GSH/GSSG ratio. Conclusions: The use of gas led to drastic changes in the cell size, primary energy metabolism and internal redox balance and Eh. These changes were different depending on the gas applied throughout the culture. Significance and Impact of the Study: For the first time, our study describes the influence of various gases on the physiology of the brewing yeast S. cerevisiae. These influences concern mainly yeast growth, cell structure, carbon and redox metabolisms. This work may have important implications in alcohol‐related industries, where different strategies are currently developed to control better the production of metabolites with a particular attention to glycerol and ethanol.

Simultaneous production of 1,3‐propanediol and n‐butanol by Clostridium pasteurianum: In situ gas stripping and cellular metabolism

“…Pham et al. varied the RP of the Saccharomyces cerevisiae culture by sparging oxygen, hydrogen, and helium during EtOH fermentation. Their RP control strategies provided insights for more efficient EtOH production.…”

“…O 2 , H 2 , and CO) into fermentation systems was previously used to control the RP of different microbial cultivations [31]. Pham et al [32] varied the RP of the Saccharomyces cerevisiae culture by sparging oxygen, hydrogen, and helium during EtOH fermentation. Their RP control strategies provided insights for more efficient EtOH production.…”

Differences in stationary-phase cells of a commercial Saccharomyces cerevisiae wine yeast grown in aerobic and microaerophilic batch cultures assessed by electric particle analysis, light diffraction and flow cytometry

“…Distribution shapes could be explained by the existence of heterogeneous populations known as quiescent and non-quiescent cells [2]. Under aerobic conditions, the oxygen concentration decreases along the log phase despite the magnetic stirring, and the sample reaches the stationary phase with lower oxygen concentration [18,22]. These environmental changes, in addition to nutrient depletion and pH changes, affect the physiology of yeast that changes from respirofermentative to fermentative [33].…”

Effect of oxygen on the biosynthesis of flavor compound 3-methylbutanal from leucine catabolism during batch culture in Carnobacterium maltaromaticum LMA 28

“…Indeed, the presence of oxygen or high oxidation state results in increased production of 3-methylbutanal and 3-methylbutanol in Lactococcus lactis and Proteus vulgaris, respectively (Kieronczyk et al, 2006;Deetae et al, 2011). At the same time, enzyme activities involved in amino acid catabolism could be strongly controlled by the generation of oxidizing (NAD + ) and reducing agents (NADH, H + ) (Bourel et al, 2003;Pham et al, 2008). Anaerobic microorganisms convert pyruvate, resulting from glycolysis, into lactate through the activity of lactate dehydrogenase (LDH), generating NAD + and ATP in the absence of oxygen.…”

“…The activity of LDH has been shown to be dependent on the redox environment, exhibiting high specific activity in reducing conditions in Escherichia coli (Riondet et al, . However, in aerobic microorganisms, pyruvate formation from glycolysis generates more NADH, H + , and ATP in the presence of high dissolved oxygen concentration (DOC; Ardö, 2006;Pham et al, 2008). The presence of oxygen in culture medium, and consequently the redox environment, may have a dramatic effect on the control of amino acid catabolism.…”