Decolorization and Biodegradation of Direct Blue 2B by Mix Consortia of Bacillus

Mix consortia of Bacillus sp was used to decolorize Direct Blue dye 2B. The bacterial cultures exhibited 60 % decolorization ability within 48 h at temperature 40 o C and pH 7. Maximum rate of decolorization was observed (60%) when starch was supplemented in the medium. Decolorization of Direct Blue dye 2B was monitored by TLC, which indicated that dye decolorization was due to its degradation into unidentified intermediates. Maximum, dye-decolorizing efficiency was observed at 200 mg/l concentration of Direct dye 2B. A plate assay was performed for the detection of decolorizing ability of bacteria. Clearing zone (decolorization) was formed surrounding the bacterial culture. Decolorization was confirmed by UV-VIS spectrophotometer. The initial dye solution showed high peak at the wavelength of 540nm. Plate screening method has shown dark brown zone observed around colonies producing ligninolytic enzyme responsible for dye degradation. The pot culture experiment revealed that the Direct Blue 2B dye show phytotoxicity against Allium sativum, but, after degradation of dye, the degraded products obtained show less toxicity.