Comparison of the enzymatic digestibility of physically and chemically pretreated selected line of diploid-Miscanthus sinensis Shiozuka and triploid-M. × giganteus

The diploid Miscanthus sinensis “Shiozuka” which was selected as a high-biomass producing line, and the triploid M. × giganteus (M × G) were treated by ball milling (physical treatment) and alkaline hydrogen peroxide treatment (AHP; chemical treatment), and their structural sugar compositions and enzymatic digestibility were compared. The structural sugar content of Shiozuka was moderate and lower than that of M × G. The Klason lignin content of Shiozuka was also lower than that of M × G. However, Shiozuka was sensitive to ball milling and AHP treatment; ball milled and AHP-treated Shiozuka had higher enzymatic digestibility than ball milled and AHP-treated M × G. Shiozuka would be promising feedstock to obtain fermentable sugars with low energy consumption. Finally, enzymes for the hydrolysis of chemically treated Miscanthus were isolated from Trichoderma reesei ATCC 66589 and Penicillium pinophilum. The sugar yield could be increased by enzymatic hydrolysis of AHP-treated samples with NaOH and H2O2 and the isolated enzymes.