Efficient production of sugar via continuous enzymatic hydrolysis in a microreactor loaded with cellulase

Enzymatic hydrolysis is considered to be a restricted step for lignocellulosic bioethanol production at an industrial scale for its high production costs and low efficiency. In this study, a microreactor loaded with cellulase based on co-deposition of dopamine (DA) and polyethyleneimine (PEI) was proposed, for the first time, to efficiently hydrolyze carboxymethyl cellulose (CMC) and produce sugar. When the concentration of PEI increased from 0 to 0.5 mg mL−1, the enzyme loading was increased by 27.4%, and glucose production was increased by 33.2%. Besides, the cellulase-loaded microreactor showed better temperature adaptability than free cellulase at elevated temperatures ranging from 55 °C to 65 °C. After storage for 20 days, the cellulase-loaded microreactor retained 84.4% of its initial activity, which is 69.5% higher than the free cellulase. The yield reached 169.7 mg glucose g−1 CMC in the cellulase-loaded microreactor in 16 h. With the same amount of enzyme input, the glucose production per unit time in the cellulase-loaded microreactor is 97.2% higher than that in other reaction systems. This study demonstrated that continuous production of glucose can be achieved in the microreactor at a relatively low enzyme dosage.