Potential for ethanol production from different sorghum cultivars

This work presents the ethanol production results using three sweet sorghum cultivars. The sugar rich juice was fermented by Saccharomyces cerevisiae and Escherichia coli. The residual bagasse was further pretreated by dilute phosphoric acid steam explosion. The resulting slurry was submitted to Liquefaction plus Simultaneous Saccharification and co-Fermentation (L + SScF) process using Novozymes Cellic CTec3 enzymes and an engineered ethanologenic E. coli strain. Results show a sugar concentration in the juice ranging from 140 to 170 g/L, which were almost completely converted into ethanol by yeast. Concerning the L + SScF, the final ethanol concentration produced increased with enzyme dosage, with little difference among all three sorghum cultivars, reaching up to 27.5 g EtOH/L at enzyme concentrations of 11.5 FPU/gDW. Considering the ethanol produced from juice and from Sweet Sorghum Bagasse (SSB), there is a potential of producing up to 10,600 L of ethanol per hectare, improving on the values reported for corn ethanol.