Production of 2-phenylethanol from L-phenylalanine by a stress tolerantSaccharomyces cerevisiaestrain

Abstract

Screening for a robust, stress tolerant Saccharomyces cerevisiae strain for production of 2-phenylethanol (PEA) from l-phenylalanine. Saccharomyces cerevisiae natural isolates that include thermotolerant and multi-stress resistant strains were screened for production of PEA. The strains were compared by their growth rate, maximum biomass dry weight and production yields, and it was shown that high biomass is required for obtaining high concentrations of PEA. One thermotolerant strain, Ye9-612, was the most efficient, and under optimal conditions produced 0.85 g l(-1) PEA in shaking flasks, and 4.5 g l(-1) in a fed-batch fermentation. Strain Ye9-612 was also found to be tolerant to high concentrations of PEA, and maintained high biomass dry weight in the presence of 2.5 g l(-1) PEA. We found a highly productive thermotolerant S. cerevisiae strain that is resistant to high concentrations of PEA. PEA is inhibitory to growing yeast cells and therefore a robust strain is needed for excessive industrial production. This is the first description of such a stress tolerant strain, and the PEA concentration obtained in the fermentation is the highest reported to date.