Effect of diluted hydrolysate as yeast propagation medium on ethanol production.

Yeast propagation using 50% diluted hydrolysate in water was utilized for the fermentation of hydrolysate derived from pre-treated ensiled sweet sorghum. The purpose was to condition the yeast to the inhibitors generated during the ensiling of sweet sorghum. The conditioned seed cultures exhibited similar fermentation performance and superior kinetics than the inoculum prepared in YPD medium. Furthermore, the conditioned yeast showed increased tolerance to the increased levels of these inhibitors, including ethanol, acetic and lactic acids, demonstrating an effective way to increase the robustness of yeast fermentation for ethanol production.