Immobilization of alcohol dehydrogenase on the surface of polyethylene membrane

Using polyacrylic acid (PAA) modified polyethylene (PE) membrane as a carrier, two immobilization routes of alcohol dehydrogenase (ADH) were studied, and the catalytic performance of immobilized enzyme was investigated using formaldehyde as a substrate. In the first route, PAA-PE membrane was further modified by polyethyleneimine (PEI) and then ADH was covalently linked by glutaraldehyde (GA) to the surface of PEI/PAA-PE. The results show that the optimal immobilization pH was 6.0, immobilization temperature was 5—15℃, ADH and GA concentrations were 1.0mg/ml and 0.01%(mass). For immobilized enzyme, the optimal reaction pH was 6.5, temperature was 15—30℃, and the highest reaction rate was 9.6 μmol/(L·min), the remaining activity was 47.3% after 10 use cycles. In the second route, ADH was immobilized on PAA-PE membrane with 1-(3-dimethylaminopropyl)-2-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) as activators. The results show that the optimal molar ratio of EDC and NHS was 1∶0.5, and the immobilization time was 24 h. For immobilized enzyme, the optimal reaction pH was 6.5, temperature was 20—37℃, and the highest reaction rate was 15.58 μmol/(L·min), 53.8% activity was remained after 10 cycles.