(257a) Investigation of Microbial Behavior of Yeasts in Solid State and Submerged Liquid Fermentations for Ethanol Production From Sweet Sorghum

Comparing to conventional submerged liquid fermentation (SLF), the solid state fermentation (SSF) has not found widespread application at large scale due to the barrier of heat and mass transfer, and limited understanding of behavior of microorganisms in SSF. The SSF, however, has the advantage of reducing the process cost of substrate pretreatment, lower water usage and negative impact by the waste of fermentation on environment. A novel fermentor using rotary drum concept for SSF was developed and recently, the demonstration of bioethanol production from sweet sorghum using this novel fermentor of 127 m3 in China was successfully achieved. Saccharomyces cerevisiae TSH1, applied in the fermentation, showed high efficiency of ethanol production during the course of SSF, which completed sugars utilization within 24 h using sweet sorghum containing a total sugar content of 10~14% (w/w). This study focuses on investigating the robust character of the TSH1 as compared to other yeast strains in SSF vs SLF and further offers an insight into a new approach to understand the microbial behavior in the process of SSF.