However, the maximum sugar concentration obtained in this experiment was only about 30 g/l with hydrolysis percentage of 73%. The sugar produced remained static after 72 h although the cellulase activity (indicated by β-glucosidase activity) was still detected at 2.03 U/ml (Fig. 4-a). Limited accessibility of cellulosic material by cellulase, due to the remaining lignin that coated the internal part of the cellulose and/or most of the accessible cellulose had been converted into sugar, might account for this situation. Therefore, this simultaneous process has faced a limitation, whereby the saccharification process produced insufficient amount of sugar for ABE production.
static