To evaluate decolorization and detoxification of Azure B dye by a newly isolated Bacillus sp. MZS 10 strain, the cultivation medium and decolorization mechanism of the isolate were investigated. The decolorization was...To evaluate decolorization and detoxification of Azure B dye by a newly isolated Bacillus sp. MZS 10 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. MZS 10 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.展开更多
基金supported by the Science&Technology Program of Jiangsu Province(No.BE2011623)the Scientific Research Project of Provincial Environmental Protection Bureau of Jiangsu Province(No.2012047)
文摘To evaluate decolorization and detoxification of Azure B dye by a newly isolated Bacillus sp. MZS 10 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. MZS 10 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.
