Review on Microbial Potential for Dye Remediation

Due to their structural complexity, toxic nature, and recalcitrance to conventional treatment processes, synthetic dyes, which are widely used across various industries, have become a major class of xenobiotic pollutants. The photosynthesis and oxygen balance of aquatic environments are disrupted by their persistence in aquatic ecosystems. Moreover, they also pose the risks of carcinogenicity, mutagenicity, and genotoxicity to human beings. As a sustainable alternative, microbial bioremediation has gained attention, as microorganisms degrade diverse classes of dyes by means of versatile enzymatic systems, such as azoreductases, laccase, and peroxidases. Advanced understanding of action mechanisms of the enzymes, pathways of dye degradation, and optimal degradation conditions has been summarized in this review. Critical evaluation of emerging strategies of biotechnology, omics-based profiling, genetic engineering, enzyme immobilization, and hybrid systems that integrate microbial processes with phytoremediation, microbial fuel cells, nanotechnology, and phytoremediation has been carried out. The review indicates that engineered microbial strains and naturally assembled consortia are viable candidates for the biodegradation and detoxification of dyes, particularly because they can sustain activity even under environmentally harsh or growth-limiting conditions. Furthermore, as an inevitable approach, in silico methods guide to design and optimize the interfering biocatalytic systems by providing tools to understand the molecular interactions between dyes and enzymes. Presently, the challenges of microbial dye remediation include limited degradation efficiency optimization, poor metabolic toxicity assessment, heterogeneous microbial performance across environmental variables, incomplete degradation, competition with native species, focus merely on decolorization rather than detoxification, and lack of industrial deployment. This review suggests that future studies should focus on system-level integration, synthetic biology approaches for optimizing enzymes, multispecies microcosm studies, optimization of dye-specific microbial consortia, employing native species in biomass-to-bioenergy production, and multilevel toxicological, techno-economic, and life cycle assessments.