Preparation of porous chitosan/GPTMS hybrid membrane and its application in affinity sorption for tyrosinase purification with Agaricus bisporus

In this study NaCl particles (porogen) and γ-glycidoxypropyltrimethoxysilane (GPTMS) (cross-linking agent) were used to make chitosan–silica porous hybrid membranes. An optimal chitosan/GPTMS weight ratio 1:1 was found to prepare a novel CSG1.0 membrane. Both macropores (10.72–202.29 μm) in the membrane matrix and micropores (0.008–0.01 μm) in the skeleton of the macropores were observed on CSG1.0.Five compounds, histidine, glutamic acid, tyrosine, l-DOPA, and p-aminobenzoic acid were individually grafted onto CSG1.0. They are linked as ligands by genipin for affinity adsorption of tyrosinase from a crude Agaricus bisporus solution. This study indicates the p-aminobenzoic acid (ABA) grafted chitosan membrane (CSG-ABA) exhibited the best sorption capacity on tyrosinase. Only one band on SDS-PAGE gel was found from the eluted protein of CSG-ABA that identified the selective adsorption of CSG-ABA on tyrosinase.The behavior of tyrosinase sorption by CSG-ABA followed pseudo-first order kinetics. The sorption process was exothermal, and the sorption capacity decreased as the operation temperature increased. The negative value of the sorption ΔS° showed the tyrosinase sorption by CSG-ABA was enthalpic dominant.This study shows CSG1.0 membrane is suitable to be modified for bioproduct separation.