Efficient high-solids enzymatic hydrolysis of corncobs by an acidic pretreatment and a fed-batch feeding mode

Corncob is an abundant and renewable resource that could be enzymatically hydrolyzed to fermentable sugar. A major impediment in corncob utilization is the low hydrolysis efficiency at high-solids content. This study attempted different pretreatment methods and fed-batch modes to achieve a 25% solids content hydrolysis with high yields. Natural corncobs were compared with acid-treated and acid-alkali-treated corncobs in terms of kinetics parameters, conversion rate and glucose titer. By feeding in batches, a "low amount and high frequency" mode (10%-3%-3%-3%-3%-3%, every 5 h) was confirmed to be optimal for a 25% high-solids hydrolysis system with a cellulase loading of 12 mg/g (7.3 FPU/g), resulted with an 84.4% glucose yield at 96 h. Our results demonstrated that combination of both optimized pretreatment method and fed-batch mode were a favored process model for high-solids hydrolysis of lignocellulose, boosting cellulose hydrolysis efficiency and sugar yields on an industrial scale.