Abstract:
Effective effluent treatment is a paramount step towards conserving the dwindling clean water resources. The present study
describes the use of crude protease extract from Bacillus Cereus Strain KM201428 biotransformation of azo dye Reactive Black
5 (RB5). Batch experimental results displayed over 97% decolorization efficiency with initial dye concentration of 1.0 x 10-4M.
The decolorization process was highly dependent on contact time, dye concentration and pH. The optimum contact time and pH
for decolorization were 120 hours and pH 9 respectively at 25˚C. Biotransformation of RB5 dye was monitored using UV-Vis
spectrophotometer and formed metabolites characterized by LC–QTOF-MS. Comparison of resultant LC–QTOF-MS
chromatograms after decolorization confirmed complete cleavage of RB5 dye. First order kinetic fitted well with experimental
data for different RB5 dye concentrations. Lineweaver-Burk plot was used to describe the apparent relationship between the
decolorization rate and the dye concentration at optimized condition with the coefficient of determination R2
=1. This study
comprehensively illustrates the potential of crude protease from Bacillus Cereus Strain KM201428 as an effective and
environmentally friendly bacterial isolate in biodegradation of RB5 and opens a new approach in the treatment of wastewaters
contaminated with high load of azo dyes
