Optimized Decolorization of Methylene Blue by Bacillus cereus: A Genomic and Analytical Approach

Synthetic dyes, such as methylene blue (MB), constitute a major category of environmental pollutants due to their toxicity, persistence, and resistance to standard treatment methods. In this study, Bacillus cereus BC WW Saida was isolated from the heavily polluted Saida dumpsite in Lebanon and evaluated for its MB degradation efficiency. The isolate was identified through whole-genome sequencing, which revealed the presence of key enzymatic systems involved in azo dye degradation. Under optimized conditions, the strain achieved 82% decolorization, as determined by optical density measurements using a microplate reader. The process was further examined using High-Performance Liquid Chromatography (HPLC), which revealed a significant reduction in the original dye peak and the emergence of new intermediate products. These findings suggest the strong biodegradation capability of B. cereus BC WW Saida isolated from contaminated environments and highlight its potential application in the eco-friendly treatment of azo dye-contaminated wastewater.