Breaking the Ring: Mechanistic Insights Into the Biodegradation of Methylene Blue by Stenotrophomonas maltophilia

Abstract

The continuous discharge of methylene blue (MB) and other synthetic dyes from textile industries poses significant environmental and public health challenges due to their persistence, toxicity, and resistance to conventional wastewater treatment methods. Among various microbial candidates, Stenotrophomonas maltophilia has emerged as a promising bacterium because of its remarkable metabolic versatility and ability to degrade a wide range of xenobiotic pollutants. This review critically summarizes recent advances in the biodegradation of MB by S. maltophilia , with emphasis on its genomic characteristics, metabolic adaptability, oxidoreductase enzyme systems, and biodegradation mechanisms. The roles of key enzymes, including laccase, multicopper oxidase, NADH‐DCIP reductase, and triphenylmethane reductase, together with the physicochemical factors influencing biodegradation, are comprehensively discussed. Recent developments in biofilm‐based systems, immobilized‐cell technology, microbial consortia, and metabolic engineering are also highlighted to improve degradation efficiency and industrial applicability. In addition, this review critically examines the dual role of S. maltophilia as both an efficient bioremediation agent and an opportunistic multidrug‐resistant pathogen, emphasizing the associated biosafety concerns. Finally, current research gaps, future perspectives, and emerging strategies, including advanced omics, CRISPR‐based strain engineering, and pilot‐scale validation, are discussed to facilitate the safe and sustainable application of S. maltophilia in industrial dye wastewater remediation.