Enzymatic hydrolysis of organosolv Kanlow switchgrass and its impact on cellulose crystallinity and degree of polymerization

Abstract

In this work the potential of organosolv treated Kanlow switchgrass for ethanol production was determined and the changes imparted to cellulose crystallinity and degree of polymerization (DP) along the course of enzymatic hydrolysis were assessed. The organosolv pretreatment yielded a substrate that was readily hydrolyzed by cellulases allowing 92.0% recovery of the glucan present in untreated switchgrass after 72 h of enzymatic hydrolysis. Cellulose crystallinity remained approximately constant after organosolv pretreatment and additionally during the course of enzymatic hydrolysis (8 h of enzymatic hydrolysis). The degree of polymerization decreased upon organosolv pretreatment. During enzymatic hydrolysis the DP decreased for the first two hours and thereafter remained approximately constant (4–8 hours). The polydispersity index showed a small increase along the course of enzymatic hydrolysis (0–8 hours). The obtained results indicated the occurrence of a “peeling off” type mechanism.