Enhanced biodecolorization of textile dye Remazol navy blue using an isolated bacterial strain Bacillus pumilus HKG212 under improved culture conditions

Biodegradation of synthetic dyes has been proven as the most efficient, eco-friendly and cost-effective alternative for the treatment of textile dyes contaminated waste water. Remazole Navy Blue (RNB), an azo dye used extensively in the commercial textile industry constitutes hazardous recalcitrant, when released in the aqueous environment. In this research, an isolated bacterial strain identified as Bacillus pumilus HKG212 was studied for its potential to decolorize RNB dye. The isolated bacterial strain showed significant decolorizing capacity of more than 95% up to an initial dye concentration of 500 mg/L, within 48 hours and was efficiently tolerant up to a higher concentration of 1500 mg/L, under static condition. We investigated various physicochemical parameters to achieve maximum dye degradation by Bacillus pumilus HKG212.  The optimal conditions for the decolorizing activity of Bacillus pumilus HKG212 were anaerobic culture environment with 10% innoculm volume and beef extract as a nitrogen source, at pH 8.0, and 30℃.  Biodegradation of RNB dye was confirmed through UV-VIS Spectrophotometer, HPLC and FTIR analysis. Our findings confer the potential application of strain Bacillus pumilus HKG212 for decolorization of RNB dye and hence treatment of industrial wastewaters containing dye pollutants.