Growth and fermentation under multiple stresses
Fermentation under various stress conditions was studied in semi-anaerobic fermentation conditions. Thermotolerance was assayed by growing strains under varying temperature (38°C–42°C), whereas the tolerance of the strains to ethanol and toxic inhibitors was studied by adding a known amount of ethanol (6–10% v/v) and inhibitors such as furfural (0.25–1 g/l) and 5-HMF (0.25–0.75 g/l) to the glucose synthetic media. Further, the performance of strains under the effects of multiple stresses including temperature (39°C), initial concentration of ethanol (7%), furfural (0.35 g/l) and 5-HMF concentration (0.35 g/l) was also evaluated in semi-anaerobic conditions. The control experiment was performed using the same medium at 30°C with no initial ethanol or inhibitors added.