Optimization of Substrates and Incubation Time for Dye Decolorization using Response Surface Methodology in Bacillus subtilis (MTCC-2414) and Pseudomonas putida (MTCC-2445)

The rising industrial use of dyes has resulted in un-treated effluents being discharged into water bodies, causing toxic, carcinogenic effects on humans and disrupting aquatic ecosystems. Traditional physico-chemical used for dye removal methods face limitations such as toxic by-product formation, sludge accumulation, and incomplete degradation. Microbial bioremediation offers a sustainable alternative for textile dye decolorization. This study explored the use of a microbial consortium comprising Bacillus subtilis (MTCC-2414) and Pseudomonas putida (MTCC-2445), optimizing substrate type and concentration to enhance decolorization efficiency. Response Surface Methodology (RSM) was used to identify critical parameters influencing degradation. Statistical analyses including ANOVA, Tukey’s HSD, and Principal Component Analysis (PCA), along with contour plots, helped evaluate substrate effects and visualize interactions. Among tested substrates, glucose showed the highest initial decolorization efficiency, though prolonged incubation improved results with all substrates, including sugarcane and rice bran. The findings confirm the effectiveness of Bacillus subtilis and Pseudomonas putida as bioremediation agents for treating dye-contaminated wastewater. Overall, the study supports microbial bioremediation as an eco-friendly, efficient, and sustainable approach for industrial dye pollution, offering a promising alternative to conventional methods.