Enhanced decolourization of congo red dye under submerged fermentation (SMF) process by newly isolated Bacillus subtilis SPR42

Studies were carried out on the decolourization of textile azo dye using newly isolated aerobic bacterial culture. Among the 58 strains of aerobic bacteria isolated from soil contaminated with textile industry (Shivalik polymer Ltd. Faridabad) effluent, three showed remarkable ability in decolourizing the widely utilized azo dye (Congo Red). These strains also readily grew in and decolourized the high concentrations of dye (100 mgL -1). The aerobic bacterial isolate SPR42, was able to decolourize the Congo Red dye at a concentration of 100 mgL -1 upto 94% within 24 hrs at static conditions. The temperature and pH for optimum growth and activity of the isolate were reported as 37 oC and 8.5, respectively. The colorless bacterial biomass after decolourization suggested that decolourization was due to biodegradation, rather than inactive surface adsorption. Phenotypic characterization and phylogenetic analysis based on 16S rDNA sequence comparisons indicate that the strain SPR42 identified as Bacillus subtilis. This isolate can be a potential strain for biological treatment of effluents of TPI (Textile Processing Industry)