Abstract

The spore laccase enzyme production by B. amyloliquefaciens was optimized. It was characterized and tested for its textile dye decolorization potential. LB medium was found to be the most promising growth medium with addition of glucose (1–2%), yeast extract (0.1%), FeCl₃ (0.01 mM) and MnCl₂ (0.001 mM). The optimum spore laccase production was at pH 8, 30 °C, 1:5 medium to air ratio, 2% inoculum size and 7 days incubation. The characterization study of the enzyme showed the maximum activity at 60 °C and pH 6–7.5. It was induced by Ca⁺², Mg⁺², Fe⁺³, Zn⁺², Cu⁺² and Na⁺ at 1 mM concentration. Also, it was stable in the presence of methanol, ethanol, acetone and chloroform. In addition, it enhanced about 34% by 5 mM H₂O₂ and it was nearly stable at 10–20 mM H₂O₂. Furthermore, mediators such as ABTS, syrengaldazine and 2, 6 dimethyl phenol enhanced the spore laccase activity. The spore laccase enzyme efficiently decolorized direct red 81 and acid black 24 after 24 h. Phytotoxicity of the direct red 81 solution after decolorization by tested spore laccase was lower than that of the untreated dye solution. Finally, this study added a promising spore laccase candidate for ecofriendly and cost-effective dye wastewater bio-decolorization.

摘要

优化了解淀粉芽孢杆菌的孢子漆酶生产。对其进行了表征并测试了其纺织品染料的脱色潜力。发现LB培养基是最有前途的生长培养基，添加了葡萄糖（1-2％），酵母提取物（0.1％），FeCl ₃（0.01 mM）和MnCl ₂（0.001 mM）。最佳的孢子漆酶生产条件是在pH 8、30°C，中空比为1：5、2％接种量和7天孵育的情况下。对该酶的表征研究表明，在60°C和pH 6–7.5时具有最大活性。Ca ⁺²，Mg ⁺²，Fe ⁺³，Zn ⁺²，Cu ⁺²和Na ⁺诱导浓度为1 mM。而且，它在甲醇，乙醇，丙酮和氯仿存在下稳定。此外，它通过5 mM H ₂ O ₂增强了约34％，在10–20 mM H ₂ O ₂处几乎稳定。此外，诸如ABTS，syrengaldazine和2，6二甲基苯酚之类的介质可增强孢子漆酶活性。孢子漆酶在24小时后有效地使直接红81和酸性黑24脱色。经测试的孢子漆酶脱色后，直接红81溶液的植物毒性低于未处理的染料溶液。最后，这项研究为生态友好和具有成本效益的染料废水生物脱色添加了有希望的孢子漆酶候选物。