Optimization for decolorization of azo dye Remazol Black B by a Halomonas strain using the Taguchi approach

Halophilic and halotolerant microorganisms are good candidates for decolorization of azo dyes which are routinely used in the dyeing process in textile industries. In this paper, theoptimization of biological decolorization of synthetic dye solutions containing Remazol Black B by the previously isolated halophilic bacterium Halomonas sp. D2 is investigated. In a primary investigation using a one-factor–at-a-time method, temperature, initial pH of the solution, and concentrations of glucose, yeast extract, and sodium chloride were chosen for optimizing dye removal using the Taguchi method. Based on the statistical analysis of the results, the most significant parameter by far was the yeast extract concentration which accounted for 72.67% of the total effect, followed by pH (11.84%) and the NaCl concentration (8.90%). The optimized conditions for dye removal were predicted to be a temperature of 35°C, an initial pH of 10, glucose concentration of 1% (w/v), yeast extract concentration of 1% (w/v), and sodium chloride of 10% (w/v). Under these conditions, 95% decolorization was achieved in confirming experiments.