화학공학소재연구정보센터
Biotechnology and Bioengineering, Vol.51, No.1, 79-86, 1996
Tyrosinase-Containing Chitosan Gels - A Combined Catalyst and Sorbent for Selective Phenol Removal
There are a series of examples in which phenols appear as contaminants in process streams and their selective removal is required for waste minimization. For the selective rem oval of a phenol from a mixture, we are exploiting the substrate specificity of the enzyme tyrosinase to convert phenols into reactive o-quinones which are then adsorbed onto the amine-containing polymer chitosan. To effectively package the enzyme and sorbent, tyrosinase was immobilized between two chitosan gel films. The entrapment of tyrosinase between the films led to little loss of activity during immobilization, while tyrosinase leakage during incubation was limited. The chitosan gels rapidly adsorb the tyrosinase-generated product(s) of phenol oxidation while the capacity of the gels is substantially greater than the capacity of chitosan flakes. The performance of tyrosinase-containing chitosan gels significantly depends on the ratio of tyrosinase-to-chitosan. High tyrosinase-to-chitosan ratios result in less efficient use of tyrosinase, presumably due to suicide inactivation. However, the efficiency of chitosan use increases with increased tyrosinase-to-chitosan ratios.