Enhancement of enzymatic digestibility of Miscanthus by electron beam irradiation and chemical combined treatments for bioethanol production

• Korean Miscanthus was pretreated by electron beam irradiation (EBI).
• The optimal irradiation was determined as 500 kGy of total exposed energy at 7.4 mA and 1 MeV.
• The thermo-chemical treatments combined with EBI was performed.
• Alkali + EBI combined treatment shows the highest glucose conversion (87.97%).
• The ethanol yield was about 96.8% by hydrolysate from pretreated Miscanthus.

In this study, Korean Miscanthus sinensis was pretreated by electron beam irradiation (EBI) and then enzymatically hydrolyzed for fermentable sugar production. The total exposed energy (kGy) on Miscanthus which is considered as a significant factor in the pretreatment was investigated to obtain the optimal condition. As a result, total dose was determined as 500 kGy at 7.4 mA and 1 MeV and glucose conversion was about 1.26-fold enhanced compared with control (none treatment). To enhance the enzymatic digestibility, the thermo-chemical treatments combined with EBI was performed by sulfuric acid and aqueous ammonia. The result indicates that aqueous ammonia with EBI treatment shows the highest glucose conversion (87.97%) and 32.3% of biomass to glucose recovery which is 2.4-fold enhanced than control. Finally, the hydrolysate from pretreated Miscanthus was utilized to ethanol production by Saccharomyces cerevisiae K35 and the ethanol yield was about 96.8%.