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

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.