In-situ corn fiber conversion improves ethanol yield in corn dry-mill process
2018
Li, Xiujuan | Chen, Sitong | Huang, He | Jin, Mingjie
Dry-mill process has been widely applied for ethanol production from corn. However, corn kernel fiber (mostly cellulose) is typically unconverted in the process. This work investigated the effect of corn cellulose conversion on the performance of dry-mill process. Solid loading and pH were optimized first for better design of cellulose conversion in the process. Cellulase was dosed for cellulose conversion during Simultaneous Saccharification and Fermentation (SSF). Addition of cellulase improved ethanol yield by 1.8% compared to traditional SSF without cellulase. Cellulose conversion reached 19.8%. Starch conversion was also enhanced from 98.3% to 99.0% with glycerol yield, which is a major side-product of ethanol fermentation, decreased by 7.3%. Residual starch and residual cellulose resulted from SSF were further studied for their degradability and it was found that 63.2% of residual starch and 14.3% of residual cellulose could be further degraded in the absence of ethanol. This work implies that cellulose conversion is of great benefit to corn ethanol process.
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