Response to different environmental stress conditions of industrial and laboratory Saccharomyces cerevisiae strains.

Two sets of Saccharomyces cerevisiae strains were compared for their physiological responses to different stress conditions. One group is composed of three strains adapted to controlled laboratory conditions (CEN.PK, LR88 and RS58), whereas the other consisted of five industrial strains (IND1101, SuperStart, LO24, LO41 and Azteca). Most industrial strains showed higher tolerance to heat shock and to an oxidative environment than laboratory strains. Excluding CEN.PK, a similar behavior was observed regarding ethanol production in high sugar concentrations (180 g/l glucose). Addition of acetate (10 g/l) or furfural (2 g/l), in concentrations similar to those found in sugar cane bagasse hydrolysates, decreased cell mass formation and growth rate in almost all strains. CEN.PK and SuperStart showed the highest sensitivity when grown in furfural-containing medium. Acetic acid treatment severely affected cell mass formation and reduced growth rate in all strains; CEN.PK and LO24 were the most resistant. The specific ethanol production rate was not affected by furfural addition. However, specific ethanol production rates decreased in response to acetic acid in four industrial strains, and increased in all laboratory strains and in LO24. No significant correlation was found between the stress tolerance of the strains tested and the transcript accumulation of genes selected by their involvement in the response to each of the stressful environments applied.