The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China; School of Biological and Chemical Engineering, Nanyang Institute of Technology, Nanyang 473004, China.
The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China.
J Environ Sci (China). 2014 May 1;26(5):1125-34. doi: 10.1016/S1001-0742(13)60540-9.
To evaluate decolorization and detoxification of Azure B dye by a newly isolated Bacillus sp. MZS10 strain, the cultivation medium and decolorization mechanism of the isolate were investigated. The decolorization was discovered to be dependent on cell density of the isolate and reached 93.55% (0.04 g/L) after 14 hr of cultivation in a 5 L stirred-tank fermenter at 2.0 g/L yeast extract and 6.0 g/L soluble starch and a small amount of mineral salts. The decolorization metabolites were identified with ultra performance liquid chromatography-tandem mass spectroscopy (UPLC-MS). A mechanism for decolorization of Azure B was proposed as follows: the C=N in Azure B was initially reduced to -NH by nicotinamide adenine dinucleotide phosphate (NADPH)-dependent quinone dehydrogenase, and then the -NH further combined with -OH derived from glucose to form a stable and colorless compound through a dehydration reaction. The phytotoxicity was evaluated for both Azure B and its related derivatives produced by Bacillus sp. MZS10 decolorization, indicating that the decolorization metabolites were less toxic than original dye. The decolorization efficiency and mechanism shown by Bacillus sp. MZS10 provided insight on its potential application for the bioremediation of the dye Azure B.
为了评估新分离的芽孢杆菌 MZS10 菌株对 Azure B 染料的脱色和解毒作用，研究了该分离物的培养介质和脱色机制。发现脱色依赖于分离物的细胞密度，在 5 L 搅拌罐发酵罐中以 2.0 g/L 酵母提取物和 6.0 g/L 可溶性淀粉和少量无机盐培养 14 小时后，脱色率达到 93.55%（0.04 g/L）。使用超高效液相色谱-串联质谱（UPLC-MS）鉴定了脱色代谢产物。提出了 Azure B 脱色的机制如下：Azure B 中的 C=N 最初被烟酰胺腺嘌呤二核苷酸磷酸（NADPH）依赖性醌脱氢酶还原为-NH，然后 -NH 通过脱水反应与葡萄糖衍生的 -OH 进一步结合形成稳定的无色化合物。评估了 Bacillus sp. MZS10 脱色产生的 Azure B 及其相关衍生物的植物毒性，表明脱色代谢物的毒性比原始染料低。芽孢杆菌 MZS10 表现出的脱色效率和机制为其在 Azure B 染料的生物修复中的潜在应用提供了思路。
