Qing Qiu

Plastic pollution has become an increasingly severe global environmental issue, highlighting the urgent need for efficient and sustainable biodegradation strategies. In this study, an enriched gut microbial consortium, NE-01 derived from Tenebrio molitor, exhibited significant degradation activity toward polystyrene (PS), polyethylene (PE), and polyethylene terephthalate (PET). Metagenomic sequencing revealed that Pseudomonas and Proteobacteria were the dominant taxa, maintaining high community diversity and providing a microbial foundation for the degradation of plastics and other complex organic compounds. Functional annotation and metabolic pathway analysis indicated that xenobiotic biodegradation and metabolism occupied a large proportion of the metabolic network, suggesting the consortium’s potential for degrading exogenous pollutants. Several key genes associated with the degradation of aromatic and halogenated compounds, such as benzoate, toluene, styrene, and bisphenol A, were identified. Metabolic reconstruction further suggested possible degradation pathways for PS, PE, PET, and the plasticizer di(2-ethylhexyl) phthalate (DEHP). This study preliminarily demonstrated that the T. molitor gut-derived microbial consortium harbors multiple plastic-degrading genes and provides a theoretical basis for developing green, microbe-based strategies for plastic degradation.

As a widespread pollutant, bisphenol A (BPA) has created a serious threat to ecosystem and human health. Therefore, expanding the available microbial resources used to screen highly efficient BPA-degrading bacteria with BPA as the sole carbon source is very important for the removal of this pollutant from the environment. In this study, the BPA degradation rate of Pseudomonas sp. P1 to 30 mg/L was 96.89% within 120 h. Whole genome sequencing showed that the genome of strain P1 was composed of a single circular chromosome with a full length of 6.17 Mb, which contained 5636 predicted coding genes. Comparative genomic analysis showed that strain P1 contained 210 functional genes related to BPA degradation. It was confirmed that BPA degradation genes ferredoxin (bisdA), P450 (bisdB), CotA and Lac in strain P1 were highly expressed under the induction of BPA. Combined with the identification of metabolites, the route of BPA degradation by Pseudomonas was proposed. A new metabolite, 4-vinylphenol, was detected for the first time in pathway Ⅰ. In pathway Ⅱ, BPA is directly oxidized to phenol and 4-isopropenyl phenol in the presence of laccase, which is rarely reported in the process of bacterial degradation of BPA. This study confirmed that strain P1 had good tolerance to various environmental factors at the gene level and enriched the degradation mechanism of BPA.

Bisphenol A (BPA) pollution poses an increasingly serious problem. BPA has been detected in a variety of environmental media and human tissues. Microbial degradation is an effective method of environmental BPA remediation. However, BPA is also biotoxic to microorganisms. In this study, Rhodococcus equi DSSKP-R-001 (R-001) was used to degrade BPA, and the effects of BPA on the growth metabolism, gene expression patterns, and toxicity-resistance mechanisms of Rhodococcus equi were analyzed. The results showed that R-001 degraded 51.2% of 5 mg/L BPA and that 40 mg/L BPA was the maximum BPA concentration tolerated by strain R-001. Cytochrome P450 monooxygenase and multicopper oxidases played key roles in BPA degradation. However, BPA was toxic to strain R-001, exhibiting nonlinear inhibitory effects on the growth and metabolism of this bacterium. R-001 bacterial biomass, total protein content, and ATP content exhibited V-shaped trends as BPA concentration increased. The toxic effects of BPA included the downregulation of R-001 genes related to glycolysis/gluconeogenesis, pentose phosphate metabolism, and glyoxylate and dicarboxylate metabolism. Genes involved in aspects of the BPA-resistance response, such as base excision repair, osmoprotectant transport, iron-complex transport, and some energy metabolisms, were upregulated to mitigate the loss of energy associated with BPA exposure. This study helped to clarify the bacterial mechanisms involved in BPA biodegradation and toxicity resistance, and our results provide a theoretical basis for the application of strain R-001 in BPA pollution treatments.

This study assessed the toxic effects of bisphenol A (BPA) on the microbial community and the function of activated sludge in sequencing batch reactors (SBRs). The toxicity of BPA was mitigated through dosing sludge with Rhodococcus Req-001. BPA reduced the biomass of sludge, and the proportion of viable bacteria decreased with the aggravation of BPA pollution. BPA affected the secretion of extracellular polymeric substances (EPSs), increased the ratio of polysaccharide to protein, and deteriorated the sedimentation performance of sludge. BPA decreased the abundances of functional bacteria involved in the degradation of organic matter and water purification, including Polaromonas, Dechloromonas, and Nitrospira, and the water purification capacity of the reactor decreased. Req-001 enhanced the BPA removal efficiency by 15%, and increased ammonia nitrogen and phosphorus removal by 8.8% and 22.7%, respectively. The functional recovery ability of the sludge system and the high removal ability of Req-001 make it a promising specie for use in BPA bioremediation. This study combined the effect of BPA on activated sludge and reactor performance with the microbial community, clarified the toxic mechanism of BPA on activated sludge, and therefore provides a theoretical basis and potential solutions to help WWTPs cope with the toxic effects of BPA.