Journal of Pure and Applied MicrobiologyVol. 9 No. 1

Decolorization of SN4R Dye by a Recombinant Laccase from Pichia pastoris

Miao-Miao Zheng1, Shu-Li Shao1*, Hong-Wei Yi2, Peng Wu1, Bo Li1, Ying Zhai1, Zhan-Zhan Jiao1 and Lin-Gang Zhang1

1Key Laboratory of Industrial Microbiology, Qiqihar University, Qiqihar, Heilongjiang, People?s Republic of China. 2Institute of fruit tree, Chongqing Academy of Agricultural Sciences, Chongqing, People?s Republic of China.

Received on 27 July 2014 and accepted on 11 October 2014

 

ABSTRACT

This study is the first report on synthetic dye decolor by recombinant Pleurotus djamor laccase. A cDNA encoding for a laccase was isolated from the white-rot fungus P. djamor was isolated by RT-PCR and expressed in the P. pastoris strain SMD1168H under the control of the alcohol oxidase (AOX1) promoter. The laccase native signal peptide efficiently directed the secretion of the recombinant laccase in an active form. Factors influencing laccase expression, such as pH, cultivation temperature, copper concentration and methanol concentration, were investigated. The recombinant enzyme was purified to electrophoretic homogeneity, and was estimated to have a molecular mass of about 62.5 kDa. The purified enzyme behaved similarly to the native laccase produced by P. djamor and efficiently decolorized four synthetic dyes including azo, anthraquinone, heterocyclic and triphenylmethane dyes, without the addition of redox mediators. The decolorization capacity of this recombinant enzyme suggests that it could be a useful biocatalyst for the treatment of dye-containing effluents.

Keywords : Dye decolorization, Pichia pastoris, Purification, Recombinant laccase.