Mixed culture of Saccharomyces cerevisiae and Acetobacter pasteurianus for acetic acid production

Biosynthesis of cell membrane lipids is a crucial metabolic pathway for the growth and viability of eucaryotic microorganisms. In Saccharomyces cerevisiae, unsaturated fatty acids and ergosterol synthesis needs molecular oxygen. Stuck and sluggish fermentations are related to this aspect of metabolism and constitute a major problem in the wine industry. Anaerobiosis, when lipids are not available in the growth medium, highly stresses cells. They release lipid biosynthesis metabolites and soon cease to multiply. This paper describes an investigation of the nutritional role of exogenous lipids from inactivated yeast cells (IYCs). Fermentations were carried out in a nitrogen-rich synthetic medium similar to grape juice with glucose and fructose as carbon sources, without lipid sources, and in anaerobiosis. The effect of the addition of IYC was assessed. Cell growth, cell lipid composition, glucose and fructose consumption, and acetic acid production were measured during fermentation. Addition of IYC boosted cell growth and sugar consumption, whereas acetic acid production decreased. Biomass yield was influenced by ergosterol availability and increased when IYCs were added. Fatty acid composition of yeast cells was changed by IYC addition.Key words: fermentation, lipids, nutrition, Saccharomyces cerevisiae, wine.

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Candida zemplinina Can Reduce Acetic Acid Produced by Saccharomyces cerevisiae in Sweet Wine Fermentations

Applied and Environmental Microbiology ◽

10.1128/aem.06768-11 ◽

2012 ◽

Vol 78 (6) ◽

pp. 1987-1994 ◽

Cited By ~ 86

Author(s):

Kalliopi Rantsiou ◽

Paola Dolci ◽

Simone Giacosa ◽

Fabrizio Torchio ◽

Rosanna Tofalo ◽

...

Keyword(s):

Saccharomyces Cerevisiae ◽

Acetic Acid ◽

Acid Production ◽

Sugar Content ◽

Acetic Acid Production ◽

Content Type ◽

High Sugar Content ◽

Sequential Inoculation ◽

Different Strains ◽

Sweet Wine

ABSTRACTIn this study we investigated the possibility of usingCandida zemplinina, as a partner ofSaccharomyces cerevisiae, in mixed fermentations of must with a high sugar content, in order to reduce its acetic acid production. Thirty-fiveC. zemplininastrains, which were isolated from different geographic regions, were molecularly characterized, and their fermentation performances were determined. Five genetically different strains were selected for mixed fermentations withS. cerevisiae. Two types of inoculation were carried out: coinoculation and sequential inoculation. A balance between the two species was generally observed for the first 6 days, after which the levels ofC. zemplininastarted to decrease. Relevant differences were observed concerning the consumption of sugars, the ethanol and glycerol content, and acetic acid production, depending on which strain was used and which type of inoculation was performed. Sequential inoculation led to the reduction of about half of the acetic acid content compared to the pureS. cerevisiaefermentation, but the ethanol and glycerol amounts were also low. A coinoculation with selected combinations ofS. cerevisiaeandC. zemplininaresulted in a decrease of ∼0.3 g of acetic acid/liter, while maintaining high ethanol and glycerol levels. This study demonstrates that mixedS. cerevisiaeandC. zemplininafermentation could be applied in sweet wine fermentation to reduce the production of acetic acid, connected to theS. cerevisiaeosmotic stress response.

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