从土壤中筛选出1 株具有较高漆酶活性的菌株,经分子生物学方法鉴定,该菌株为芽孢杆菌属细菌,将其命名为Bacillus sp. 4bs。菌株4bs 的最适生长温度和pH 分别为37 ℃和7.0,其在6%(w/v)NaCl 溶液中能够正常生长,在含有2.0 mmol/L Cu2+的培养基中仍生长旺盛。以丁香醛连氮为底物,菌株4bs 的芽孢漆酶活性为35.66U/g(干重),其芽孢漆酶最适反应温度为80 ℃,最适反应pH 值为6.8;0.1 mmol/L 的半胱氨酸、二硫苏糖醇和叠氮化钠抑制其活性,10 mmol/L 的Na+、K+、Cu2+和Li+能够增强其活性。在pH 6.8 的体系中,菌株4bs 芽孢漆酶对结晶紫和茜素红在6 h 内的脱色率分别为83.57%和77.16%;加入乙酰丁香酮(Ace)作介体时,对靛红的脱色率由52.73%提高到94.98%,对活性黑5 的脱色率由19.01%提高到90.10%。
A novel strain showing high laccase activity was separated from soil using screening agent, the strain wasidentified as Bacillus from classical and molecular biological methods, and named by Bacillus sp. 4bs. The optimumtemperature and pH for the strain growth was 37 ℃ and 7.0, respectively. It cloud normal grow in solution of 6% NaCl(w/v) or 2.0 mmol/L Cu2+. The spore laccase activity was 35.66 U/g by dry weight in the substrate with syringaldazine.The optimum reaction temperature and pH for spore laccase of the strain was 80 ℃ and 6.8, respectively, its activitycould be strongly inhibited with 0.1 mmol/L Cysteine, DTT, and NaN3, while, 10 mmol/L Na+, K+, Cu2+, and Li+ couldincrease its activity. The spore laccase of the strain could decolorize 83.57% of crystal violet and 77.16% of alizarin red atpH 6.8 without mediator, however, the decolorization rate of isatin and reactive black 5 was increased from 52.73% and19.01% to their 94.98% and 90.10% respectively when acetosyringone was added as a mediator.