Optimisation of process parameters for bioreduction of azo dyes usingBacillus firmusunder batch anaerobic condition

Optimization of Direct Blue-14 dye degradation by Bacillus fermus (Kx898362) an alkaliphilic plant endophyte and assessment of degraded metabolite toxicity

Alkaliphilic bacteria possesses the ability to survive in the extreme conditions with high salt concentrations. The adaptability of alkaliphilic bacteria to extreme conditions has made them predominant degrader in the field of biodegradation. A moderately alkaliphilic endophyte was isolated from Centella asiatica with a potential to degrade a di-azo dye Direct Blue-14(DB-14). The isolate was identified as Bacillus fermus with 97% similarity strain Xmb064. On optimization, maximum of 92.76% biodegradation was attained with dye concentration at 68.78 ppm supplemented with 1 g of sucrose and 2.5% (v/v) of inoculum for 72 h incubation. Characterization of the biodegraded product carried out using UV-vis spectrophotometry, FT-IR and LC-MS confirmed the destabilization of di-azo bond followed with the degradation of DB-14. Cytogenotoxicity studies revealed the biodegraded products to be less toxic. The current study is the first report on the optimization, biotransformation and cytogenotoxicity of DB-14 by B. fermus strain Centella.