A review of microbial degradation of pyridine in wastewater: Degrading microorganisms, metabolic pathways, and enhancement strategies

Pyridine is a persistent pollutant that is carcinogenic, teratogenic, and mutagenic, posing significant risks to both the environment and human health. Microbial technology has emerged as a promising and sustainable alternative to traditional physicochemical methods for the remediation of pyridine, owing to its environmental friendliness, specificity, and high degradation efficiency. This review summarizes the reported genera of pyridine-degrading bacteria, their degradation characteristics, and the mechanisms of hydroxylation, methylation, ring cleavage, and mineralization. We provide a systematic analysis of the catabolic pathways, key enzymes, particularly emphasizing the central role of monooxygenases, and intermediates. Given that efficient pyridine degradation in complex environments is challenging for single strains, we propose constructing defined microbial consortia by harnessing pyridine-degrading enzymes and genes to enhance degradation and mineralization. Furthermore, we highlight the integration of microbial systems with enhancement strategies, such as Fenton pretreatment, electrostimulation, and immobilization techniques, which have been identified as effective approaches for treating high-concentration pyridine wastewater and reducing intermediate accumulation. In summary, this review aims to synthesize recent advances in pyridine biodegradation, comprehensively explore the potential of microbial systems for pyridine removal, and provide a foundational reference for future research and application development.