Abstract
The salt-tolerant strain, isolated from textile wastewater, has been found effective on decolorizing several kinds of azo dyes with different structures. The optimal conditions for azo dye acid red B (ARB) decolorization by were determined to be pH= 7.0 and 30°C. The decolorization efficiency increased with the increase of the salinity concentration, and around 90% of ARB (100 mg·L ) could be decolorized in 24 h when the salinity concentration was up to 50 g·L . Moreover, the strain could still decolorize 19% of ARB in 24 h even when the NaCl concentration was increased to 150 g·L . Meanwhile, the dependence of the specific decolorization rate by on the ARB concentration could be described with Michaelis-Menten kinetics ( = 585.7 mg·L , = 109.8 mg·g cell ·h ). The addition of quinone redox mediator, named 2-hydroxy-1,4-naphthoquinone and anthraquinone-2,6-disulfonate, significantly accelerated the decolorization performance of . Furtherly, the activities of azoreductase (0.55 μmol·mg protein ·min ) and Nicotineamide adenine dinucleotide-dichlorophenol indophenol (NADH-DCIP) reductase (8.9 μmol·mg protein ·min ) have been observed in the crude cell extracts of . The decolorization products of ARB were analyzed by HPLC-MS, and the results indicated the reductive pathway was responsible for azo dye decolorization by .
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