Purification and Characterization of a Temperature- and pH-Stable Laccase from the Spores of Bacillus vallismortis fmb-103 and Its Application in the Degradation of Malachite Green

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• 作者：Chong Zhang ; Shuang Zhang ; Hanwen Diao ; Haizhen Zhao ; Xiaoyu Zhu ; Fengxia Lu ; Zhaoxin Lu
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2013
• 出版时间：June 12, 2013
• 年：2013
• 卷：61
• 期：23
• 页码：5468-5473
• 全文大小：281K
• 年卷期：v.61,no.23(June 12, 2013)
• ISSN：1520-5118

文摘

Malachite green residue can affect aquaculture food safety. Bioremediation of contaminated water by enzyme treatment is an environmentally friendly and economical way to remove contaminating substances. In the present study, a temperature- and pH-stable laccase was purified from the spores of Bacillus ballismortis fmb-103 and was used to degrade malachite green. The laccase from fmb-103 (fmb-L103) was purified 15.2-fold to homogeneity (389.9 mU/mg protein with respect to ABTS as a substrate) by precipitation with 30鈥?0% (NH₄)₂SO₄, DEAE-Sephadex A-50 ion exchange chromatography, and Sephadex G-100 chromatography. fmb-L103 is a nonblue laccase with a molecular weight of 55.0 kDa and Cu content of 2.5 (mol:mol). fmb-L103 retained more than 50% activity after 10 h at 70 掳C and demonstrated broad pH stability in both acidic and alkaline conditions. The effects of inhibitors and metal ions on fmb-L103 activity were also examined. A kinetic study revealed that ABTS was a suitable substrate with a K_m of 22.7 渭mol and a V_max of 3.32 渭mol/mL/min. fmb-L103 can efficiently degrade malachite green after a 48 h treatment period in combination with a mediator, without the appearance of leucomalachite green.

Keywords:

Bacillus vallismortis fmb-103; laccase; purification and characterization; malachite green degradation