Fig. 3

Scheme of the short-term adaptive processes of S. cerevisiae to the phenolic acids. The parental strain was cultured in a 100 mL flask containing 20 mL of sterilized synthetic medium at 10% (v/v) of inoculation, 30 °C, pH 6.0, for 18 h as the seeds culture. Then, yeast cells were sequentially transferring and culturing in synthetic medium contained phenolic acids mixture at the inhibitory concentrations from low to high. IC25, IC50, IC75 and IC100 represented the synthetic media contained phenolic acids at inhibitory concentrations which could cause 25%, 50%, 75% and 100% inhibition on growth rate of the parental strain. Each batch of culture was incubated at 10% (v/v) of inoculation in 100 mL flask contained 20 mL of phenolic acid media at desired inhibitory concentration, 30 °C with agitation at 150 rpm for 12 h. The adapted strains were incubated in the synthetic medium with glucose of 60 g/L and IC75 of phenolic acids mixture for comparing growth and fermentation performance, at 30 °C agitation rate of 150 rpm for 48 h