为获得性能优良的细菌漆酶,利用含铜富集培养基从森林土壤中分离到一株具有较好漆酶活性的细菌菌株LC03,经生理生化实验和16SrDNA序列分析鉴定为解淀粉芽孢杆菌。该菌株培养6d后的芽孢漆酶活性最高,可达48.5U/g。菌株LC03的芽孢漆酶氧化底物2,2’-联氮-双-(3-乙基苯并噻唑-6-磺酸)(ABTS)和丁香醛连氮的最适pH值分别为3.8和6.8,以丁香醛连氮为底物时的最适反应温度为60℃。该芽孢漆酶具有较好的稳定性,经70℃处理10h或pH9.0条件下放置10d仍能保持漆酶活性,同时对抑制剂SDS和EDTA具有一定的抗性。Li+、Na+、Mg2+、Ca2+、Ba3+、A1“对漆酶活性有促进作用,Ag+、Mn2=、Hg2+、co2+对其抑制作用比较明显。解淀粉芽孢杆菌LC03的芽孢漆酶在高温和碱性条件下优良的稳定性为其在工业废水处理等领域的应用奠定基础。
To obtain bacterial laccase with excellent properties, enrichment medium supplemented with copper ions was used to screen laccase-producing bacterial strains from forest soil. A bacterial strain LC03 exhibiting high laccase activity was isolated and identified as Bacillus amyloliquefaciens, using physiological and biochemical tests as well as 16S rDNA sequence analysis. Strain LC03 demonstrated the highest spore laccase activity of 48.5 U/g after 6 days cultivation. Its spore laccase could oxidize 2,2'- azino-bis(3-ethylbenzthiazoline-6-sulfonate) (ABTS) and syringaldazine with optimum pH of 3.8 and 6.8, respectively. Optimal reaction temperature for the spore laccase was 60 ~C with SGZ as substrate. The spore laccase maintained high activity after incubation at 70 ℃ for 10 hours or pH 9.0 for 10 days. Meanwhile, it was also resistant to laccase inhibitors such as SDS and EDTA. The metal ions Li + , Na+, Mg2+ , Ca2+ , Ba2+ and A13+ could activate laccase activity, while other metal ions such as Ag+ , Mn2+ , Hg2+ and Co2+ demonstrated an obvious inhibition effect. The results showed that the spore laccase from B. amyloliquefaciens LC03, which possessed good stability at high temperature and alkaline conditions, could be used in many industrial fields, including wastewater treatment.