Abstract: To obtain high-yield bacterial laccase with fine stability and efficient decolorization ability，the laccase gene from Bacillus pumilus LC01 was amplified by PCR and cloned into the expression vector pPICZαA. The constructed vector pPICZαA-lac was transformed into Pichia pastoris SMD1168H. The positive P. pastoris strain was induced by methanol to produce the recombinant laccase. Then the recombinant laccase was purified and characterized. The highest laccase activity reached 1 390 U/L at 7 days after cultivation. The purified recombinant laccase had a molecular weight of 65 kD. The optimal pH and temperature for syringaldazine oxidation were 6.8 and 70℃，respectively. The initial enzyme activity was totally retained after 10 d storing at pH 9.0 and 36% of activity remained upon 10 h incubation at 70℃. The purified laccase was found to be totally inhibited by Al3+，Fe3+ and Mn2+. The purified laccase efficiently decolorized remazol brilliant blue R，reactive black 5 and indigo carmine in the presence of acetosyringone. More than 90% of the tested dyes were decolorized within 6 h at pH 9.0，indicating the recombinant laccase is an ideal candidate for the decolorization of dye effluents.

Key words: bacterial laccase, Bacillus pumilus, extracellular expression, Pichia pastoris, enzymatic property