Degradation of saccharin by a newly isolated bacterium Achromobacter sp. strain TJ-1 reduces its toxicity to HepG2 cells
摘要
Saccharin, a widely used artificial sweetener, poses significant environmental and health risks due to its persistence and bioaccumulation. The investigation involved the isolation of a new strain of saccharin-degrading bacteria, Achromobacter sp. strain TJ-1. The strain TJ-1 completely degraded 50 mg·L−1 of saccharin in 6 h, using its compound II for growth. Sucrose as carbon source and peptone as nitrogen source at 30 °C and pH 7.0 were found to be optimal for degradation. Metabolite analysis using HPLC–MS/MS proposed catechol as an intermediate which was further metabolized. Furthermore, strain TJ-1 could completely degrade 5 mg·L−1 saccharin in natural water within 6 d. Toxicity assays in HepG2 cells revealed that the degradation by strain TJ-1 significantly attenuated saccharin-induced toxicity. While transient catechol accumulation temporarily compromises cell viability, prolonged incubation with the TJ-1 strain restores cellular survival by mediating further catechol catabolism, preventing toxic accumulation and alleviating cytotoxicity. These results highlight the potent detoxification mechanism of the TJ-1 strain. This study provides the first evidence of Achromobacter-mediated saccharin degradation, offering a promising bioremediation strategy for saccharin-contaminated environments and addressing emerging concerns about artificial sweetener pollution.