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4-Chlorophenol biodegradation facilitator composed of recombinant multi-biocatalysts immobilized onto montmorillonite
- Kwean, Oh Sung, Cho, Su Yeon, Yang, Jun Won, Cho, Wooyoun, Park, Sungyoon, Lim, Yejee, Shin, Min Chul, Kim, Han-Suk, Park, Joonhong, Kim, Han S.
- Bioresource technology 2018 v.259 pp. 268-275
- 4-chlorophenol, Arthrobacter chlorophenolicus, biodegradation, catalytic activity, enzyme activity, enzyme kinetics, enzyme stability, gene overexpression, genes, hydroquinone, immobilized enzymes, kinetics, montmorillonite, oxidation, quinones
- A biodegradation facilitator which catalyzes the initial steps of 4-chlorophenol (4-CP) oxidation was prepared by immobilizing multiple enzymes (monooxygenase, CphC-I and dioxygenase, CphA-I) onto a natural inorganic support. The enzymes were obtained via overexpression and purification after cloning the corresponding genes (cphC-I and cphA-I) from Arthrobacter chlorophenolicus A6. Then, the recombinant CphC-I was immobilized onto fulvic acid-activated montmorillonite. The immobilization yield was 60%, and the high enzyme activity (82.6%) was retained after immobilization. Kinetic analysis indicated that the Michaelis-Menten model parameters for the immobilized CphC-I were similar to those for the free enzyme. The enzyme stability was markedly enhanced after immobilization. The immobilized enzyme exhibited a high level of activity even after repetitive use (84.7%) and powdering (65.8%). 4-CP was sequentially oxidized by a multiple enzyme complex, comprising the immobilized CphC-I and CphA-I, via the hydroquinone pathway: oxidative transformation of 4-CP to hydroxyquinol followed by ring fission of hydroxyquinol.