Ethanol production from disposable aspen chopsticks using delignification pretreatments

To convert waste disposable wooden chopsticks, cellulosic waste biomass, into ethanol efficiently, the effectiveness of pretreatments, i.e. ball-milling and steam explosion, for the enzymatic hydrolysis of aspen chopsticks and the dependence of substrate concentration using pretreated aspen chopsticks for the ethanol production were studied. In the enzymatic saccharification of ball-milled chopsticks, the maximum amount of glucose, 520 mg-glucoce/g-dry aspen chopsticks, was obtained from the chopsticks ball-milled for 60 min. On the other hand, the maximum amount of glucose, 598 mg-glucoce/g-dry aspen chopsticks, was obtained using steam-exploded aspen chopsticks treated at a steam pressure of 25 atm and a steaming time of 5 min. Simultaneous saccharification and fermentation (SSF) of the steam-exploded chopsticks by Meicelase and Saccahromyces cerevisiae AM12 provided 241 mg-ethanol/g-dry aspen chopsticks, corresponding to 79% of theoretical ethanol yield.