Biodegradation of crystal violet by an isolated Bacillus sp.

Synthetic dyes are widely used in the textile, cosmetic, printing, drug, and food processing industries. Triphenylmethane dyes belong to the most important group of synthetic dyes. They are generally considered as the xenobiotic compounds, which are very recalcitrant to biodegradation. Bacillus sp., was isolated from the treatment plant effluent of a textile and dyeing industry (SITEX) located in Ksar Hellal, Tunisia, decolorizes crystal violet (500 ppm) within 2.5 h under shaking condition at pH 7 and temperature 30 degrees C. The effect of dye concentration, temperature and initial pH of the solution were studied. The results obtained from the batch experiments revealed the ability of bacteria in removing dye. UV-Vis spectroscopy and FTIR analysis of samples before and after dye decolorization in culture medium confirmed decolorization of crystal violet. The phytotoxicity and microbial toxicity studies of extracted metabolites suggest the less toxic nature of them.