Fig. 6

Performance of enzymatic hydrolysis using enzymes recycled via recycling unhydrolyzed solids. Enzymatic hydrolysis was carried out on dilute alkali pre-treated corn stover or on dilute acid pre-treated corn stover for 24 h (1st round). The resulting unhydrolyzed solids were recycled to the subsequent round of enzymatic hydrolysis. Enzymatic hydrolysis was performed for 24 h for all rounds. a Effect of fresh enzyme loading in the second round enzymatic hydrolysis of dilute alkali pre-treated corn stover on glucose yield; b effect of fresh enzyme loading in the second round enzymatic hydrolysis of dilute acid pre-treated corn stover on glucose yield; c five rounds of enzyme recycling for enzymatic hydrolysis of dilute alkali pre-treated corn stover using 60% fresh enzyme loading for round 2–6; d five rounds of enzyme recycling for enzymatic hydrolysis of dilute acid pre-treated corn stover using 50% fresh enzyme loading for round 2–6