Metal-organic framework promoting high-solids enzymatic hydrolysis of untreated corncob residues.

ABSTRACT

Metal-organic frameworks (MOFs) could serve as efficient matrixes to immobilize cellulase because of their high stability and porous morphology. Herein, the Zr-based MOFs (UiO-66 and UiO-66-NH2) assisted 20 wt% high-solids hydrolysis of untreated corncob residues (CRs) at low enzyme loading was investigated. Glucan hydrolysis yields increased to 60.55% and 71.47% by separately adding 4 g/L UiO-66 and UiO-66-NH2 at 5 FPU/g-glucan cellulase dosage. The maximum hydrolysis yield reached 90.01% at 10 FPU/g-glucan in the presence of 4 g/L UiO-66-NH2. Analysis of free protein concentration and cellulase activity suggested that MOFs effectively increased cellulase catalytic activity and stability, thus boosted CRs enzymatic hydrolysis efficiency. Additionally, UiO-66-NH2 immobilization gave a high catalytic activity because of the abundant anchor sites of NH2 groups. This research presents the promising future of MOFs' application in lignocellulosic biomass bioconversion and other areas requiring immobilized enzymes.