Laccase is a promising oxidase with environmental applications, such as lignin degradation and chlorophenol detoxification. Laccase immobilization can significantly improve physiochemical stability and reusability com...Laccase is a promising oxidase with environmental applications, such as lignin degradation and chlorophenol detoxification. Laccase immobilization can significantly improve physiochemical stability and reusability compared to the free enzymes. In this work, anion effect was investigated in entrapment of Cu-alginate matrix with five types of anions, including perchlorate （ClO4）, nitrate （NO3）, sulfate （SO42 ）, chloride （Cl）, and acetate （CH3CO2-）. Accordingly, chloride inhibition and acetate activation were detected in the o-tolidine kinetic experiments, while effects of the other three anions were much smaller. Such counteranion effects were also observed in the laccase-catalyzed biodegradation of 2,4- dichlorophenol. The results indicated that counteranions in the enzyme immobilization process are crucial for catalytic capacity, probably due to the competition with the carboxylate groups in alginate. Our results also imply that these anions might coordinate the copper cations in laccase.展开更多
基金the National High-Tech R&D Program of China ‘‘863’’ (No.2012AA020403)the National Basic Research Program of China ‘‘973’’ (Nos.2012CB721005,2013CB966802)+1 种基金National Natural Science Foundation of China(Nos.21377085,21303101,31121064,J1210047)MOE New Century Excellent Talents in University(No.NCET-12-0354)
文摘Laccase is a promising oxidase with environmental applications, such as lignin degradation and chlorophenol detoxification. Laccase immobilization can significantly improve physiochemical stability and reusability compared to the free enzymes. In this work, anion effect was investigated in entrapment of Cu-alginate matrix with five types of anions, including perchlorate （ClO4）, nitrate （NO3）, sulfate （SO42 ）, chloride （Cl）, and acetate （CH3CO2-）. Accordingly, chloride inhibition and acetate activation were detected in the o-tolidine kinetic experiments, while effects of the other three anions were much smaller. Such counteranion effects were also observed in the laccase-catalyzed biodegradation of 2,4- dichlorophenol. The results indicated that counteranions in the enzyme immobilization process are crucial for catalytic capacity, probably due to the competition with the carboxylate groups in alginate. Our results also imply that these anions might coordinate the copper cations in laccase.
