An acid-stable bacterial laccase identified from the endophyte Pantoea ananatis Sd-1 genome exhibiting lignin degradation and dye decolorization abilities

• DOI: 10.1007/s10529-015-1914-1
• Publication Date: 2015-07-24T08:36:42Z
• Authors: Xiaowei Shi; Qian Liu; Jiangshan Ma; Hongdong Liao; Xianqiu Xiong; Keke Zhang; Tengfei Wang; Xuanmin Liu; Ting Xu; Shanshan Yuan; Xin Zhang; Yonghua Zhu
• Keywords: 0301 basic medicine; Pantoea; Laccase; Molecular Sequence Data; Lignin; Recombinant Proteins; 03 medical and health sciences; Bacterial Proteins; Amino Acid Sequence; Coloring Agents; Sequence Alignment; Genome, Bacterial; Water Pollutants, Chemical

Isolation and identification of a novel laccase (namely Lac4) with various industrial applications potentials from an endophytical bacterium.Endophyte Sd-1 cultured in rice straw showed intra- and extra-cellular laccase activities. Genomic analysis of Sd-1 identified four putative laccases, Lac1 to Lac4. However, only Lac4 contains the complete signature sequence of laccase and shares at most 64 % sequence identity with other characterized bacterial multi-copper oxidases. Recombinant Lac4 can oxidize non-phenolic and phenolic compounds under acidic conditions and at 30-50 °C; Km values of Lac4 for ABTS at pH 2.5 and for guaiacol at pH 4.5 were 1 ± 0.15 and 6.1 ± 1.7 mM, respectively. The activity of Lac4 was stimulated by 0.8 mM Cu(2+) and 5 mM Fe(2+). In addition, Lac4 could decolorize various synthetic dyes and exhibit the degradation rate of 38 % for lignin.The data suggest that Lac4 possesses promising biotechnological potentials.