13-05: Evaluation of Hot-Compressed Water Pretreatment with Wet Disk Milling of Japanese Hinoki and Eucalyptus using SSF and CBP Bioconversion Processes

The Japanese Biomass Technology Research Center  in the National Institute of Advanced Industrial Science and Technology (AIST) has developed an advanced pretreatment reactor which uses twin screw driven  hot-compressed water treatment (HCWT) process operated typically at 150°C in combination with wet disk milling (WDM) performed using a supermasscolloider MKZA10 (Masuko Sangyo Co., Ltd., Saitama, Japan) equipped with two ceramic nonporous disk grinders. Japanese Hinoki and Eucalyptus were pretreated with this system with multiple passes to determine the optimal performance during biomass fermentation. Two fermentation processes were used; yeast based simultaneous saccharification and fermentation (SSF) and Clostridium thermocellum-based consolidated bioprocessing (CBP) to evaluate the pretreated biomass. Experiments were also completed with American Switchgrass and Poplar which were subjected to hot water treatment (HWT) at 180°C for 40 minutes.  Results validated the efficiency of the HCWT-WDM technique as the g of fermentation products produced per g of cellulose increased with disk milling time.  A higher ethanol production was observed in Hinoki when compared to Eucalyptus.  In case of the American samples, higher ethanol production was observed in switchgrass when compared to poplar.  Overall, the conversion efficiency was about 10% better in S. cerevisiae than C. thermocellum on a fermentation product per gram cellulose basis but the processes have not been optimized.