title: A new marine bacterial laccase with chloride-enhancing, alkaline-dependent activity and dye decolorization ability.
abstract: A bacterial laccase gene designated as lac21 was screened from a marine microbial metagenomic library of the South China Sea based on sequence screening strategy. The protein encoded by lac21 shared less than 40% sequence identities with all of the laccases found. Lac21, which was recombinantly expressed in Escherichia coli, showed high activity toward syringaldazine at an optimum pH of 7.5 and temperature of 45°C. Lac21 was stable at pH values ranging from 5.5 to 9.0 and temperatures lower than 40°C. Interestingly, chloride enhanced the laccase activity, with concomitant increase in substrate affinity. Furthermore, Lac21 has high decolorization capability toward azo dyes in the absence of redox mediators, with 80% of Reactive Deep Blue M-2GE (50mg/L) being decolorized by 15U/L enzyme after 24h incubation at 20°C. These unusual properties demonstrate that the new bacterial laccase Lac21 has potentials in specific industrial or environmental applications.
authors.affiliation: School of Life Sciences, Anhui University, Hefei, Anhui 230039, China.
authors.forename: Ze-Min
authors.initials: ZM
authors.lastname: Fang
authors.forename: Tong-Liang
authors.initials: TL
authors.lastname: Li
authors.forename: Fei
authors.initials: F
authors.lastname: Chang
authors.forename: Peng
authors.initials: P
authors.lastname: Zhou
authors.forename: Wei
authors.initials: W
authors.lastname: Fang
authors.forename: Yu-Zhi
authors.initials: YZ
authors.lastname: Hong
authors.forename: Xue-Cheng
authors.initials: XC
authors.lastname: Zhang
authors.forename: Hui
authors.initials: H
authors.lastname: Peng
authors.forename: Ya-Zhong
authors.initials: YZ
authors.lastname: Xiao
mesh_terms: D000468:Alkalies / Q000378:metabolism*; D001391:Azo Compounds / Q000378:metabolism; D001483:Base Sequence; D002712:Chlorides / Q000378:metabolism*; D003116:Color; D004396:Coloring Agents / Q000378:metabolism*; D017931:DNA Primers; D004926:Escherichia coli / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D042845:Laccase / Q000378:metabolism*; D008386:Marine Biology; D011994:Recombinant Proteins / Q000378:metabolism
chemical_list: D000468:Alkalies; D001391:Azo Compounds; D002712:Chlorides; D004396:Coloring Agents; D017931:DNA Primers; D011994:Recombinant Proteins; D042845:Laccase