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

Document Type : Original Research Papers


1 Department of Biotechnology, College of Science, University of Tehran, Tehran, Iran

2 Microbiology and Biotechnology Research Group, Research Institute of Petroleum Industry, Tehran, Iran

3 Department of Microbiology, Faculty of Biology, College of Science, University of Tehran, Tehran, Iran


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, the
optimization 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


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