Ethanol production from sweet sorghum stalks by advanced solid state fermentation (ASSF) technology

Abstract:

A robust strain of the species Saccharomyces cerevisiae CGMCC1949 was screened and identified, and advanced solid state fermentation (ASSF) technology for fuel ethanol production from sweet sorghum stalks was thus developed. The fermentation time was shortened to less than 30 h, and ethanol yield was 92% of its theoretical maximum. And in the meantime, the cost-effective storage was established for sweet sorghum stalks, with less than 5% sugar loss after 200 days of storage, making the plant operation could extend up to 200 days without feedstock shortage. With the fermentation kinetics and heat-mass transfer models, modeling of the ASSF process was investigated, and the rotating drum bioreactor was designed. Furthermore, the ASSF technology was successfully applied in the pilot plant in which the rotating drum bioreactor was scaled up to 127 m3, and ethanol yield of 91% was achieved. At the end, techno-economic analysis (TEA) conducted by ASPEN indicated that ethanol production from sweet sorghum stalks by the ASSF is economically competitive.

Key words:sweet sorghum stalks, advanced solid state fermentation (ASSF), ethanol production