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Improvement of Laccase Production and its Characterization by Mutagenesis
Author(s) -
Du W.,
Sun C.,
Liang J.,
Han Y.,
Yu J.,
Liang Z.
Publication year - 2015
Publication title -
journal of food biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 47
eISSN - 1745-4514
pISSN - 0145-8884
DOI - 10.1111/jfbc.12111
Subject(s) - laccase , chemistry , mutant , ethylenediaminetetraacetic acid , strain (injury) , enzyme , biochemistry , nuclear chemistry , organic chemistry , biology , chelation , anatomy , gene
In this study, laccase production was enhanced using mutant S hiraia sp. The S hiraia sp. GZS 1 strain was mutated using ultraviolet irradiation, followed by screening of strains that were resistant to certain stressors. The mutant GZ 11 K 2 was selected and used for further studies. 2,2′‐ A zino‐bis(3‐ethylben‐zothiazoline‐6‐sulfonate) was used as substrate for both wild and mutant laccases at optimal pH (4.0). The mutant laccase exhibited a broader active pH range. The mutant laccase also showed a higher optimal catalytic temperature, more active under alkaline conditions, and higher temperature range than the wild one. The mutant strains produced higher yield of laccase than the wild strain even at high salinity of 3 g/ L NaCl . Both laccases were mildly inhibited by sodium dodecyl sulfate (0.5 m M ), ethanol (50%) and ethylenediaminetetraacetic acid (1 m M ), and almost completely inhibited by NaN 3 (20 μ M ) and DTT (1 m M ), stable in the presence of metal ions except Ag + and Hg 2+ . Practical Applications Laccase is extensively used in various applications, such as pulp delignification, decoloration, biopolymer modification, biotransformation and food dechlorination. A newly isolated laccase‐producing strain S hiraia sp. GZS 1 and a genetically stable mutant GZ 11 K 2 were established with 1.82 times laccase activity compared with that of the wild strain. The mutant S hiraia sp. GZ 11 K 2 laccase was active over a wider pH and temperature ranges and more stable than the wild strain under neutral and alkaline conditions. The laccase from the mutant GZ 11 K 2 with higher laccase productivity and enhanced enzyme properties can be used in biotechnological and industrial applications.