Evolutionary Engineering and Transcriptomic Analysis of Phenylethanol-resistant Saccharomyces cerevisiae

Phenylethanol-resistant S. cerevisiae mutants were obtained by using evolutionary engineering strategy. Briefly, a chemically mutagenized culture was used as the initial population for the selection procedure. Gradually increasing levels of phenylethanol stress was applied through 56 successive batch cultivations. Individual mutants were selected from the final population. The mutant with the highest phenylethanol resistance could resist up to 3 g/L phenylethanol concentrations. Whole-genome transcriptomic analyses of the phenylethanol-resistant mutant strain and the reference strain were performed by using DNA microarray technology, in the absence of phenylethanol stress. Agilent yeast DNA microarray systems were used for whole-genome transcriptomic analyses of the reference strain and the selected phenylethanol-resistant mutant. Three replicates of each culture were grown in 100 mL yeast minimal medium using 500 mL flasks, at 30°C and 150 rpm. Cells at logarithmic phase of growth (~1.0 OD600) were used for total RNA isolation.