Decolorization of Brilliant Blue G dye mediated by degradation of the microbial consortium of Galactomyces geotrichum and Bacillus sp.

A consortium-GB containing two microorganisms Galactomyces geotrichum MTCC 1360 and Bacillus sp. VUS was able to degrade sulfur-containing dye Brilliant Blue G, optimally at pH 9 and temperature at 50 °C. The ability of consortium-GB to work at higher temperature and pH ranges will help in using this consortium for removal of the dye from textile effluent. Malt extract, peptone and beef extract were found to be the best additional carbon and nitrogen sources. Brilliant Blue G caused enhancement of the riboflavin reductase among the enzyme activities studied. Biodegradation was confirmed by analyzing the product using UV–vis, HPLC, and FTIR. The GC–MS study revealed a pathway of Brilliant Blue G with release of (4-ethoxy-phenyl)-phenyl-amine and 3-ethylaminomethyl-benzenesulfonic acid as final metabolites formed by the consortium-GB. GC–MS analysis indicated the formation of 3-{[ethyl-(3-methyl-cyclohexa-2,5-dienyl)-amino]-methyl}-benzenesulfonic acid as a product by G. geotrichum MTCC 1360 alone and (4-benzylidene-3-methyl-cyclohexa-2,5-dienylidene)-methyl-amine by Bacillus sp. VUS alone. Phytotoxicity revealed nontoxic nature of the metabolites. These results indicate the high potential of the consortium-GB to serve as an excellent biomass for the use in Brilliant Blue G dye removal.