BIODEGRADATION OF 3-PHENOXYBENZOIC ACID BY A NOVEL SPHINGOMONAS SP. SC-1

摘要

Strain SC-1 able to degrade 3-phenoxybenzoic acid (3-PBA) completely was isolated from activated sludge being used to treat pyrethroid-manufacturer waste water, and identified as Sphingomonas based on its morphological, physiological and biochemical properties and 16S rDNA gene sequence. The strain Sphingomonas sp. SC-1 could utilize 3-PBA as sole carbon and energy sources for its growth, and 300 mg L~(-1) of 3-PBA could be degraded completely within 24 h. In addition, the degradation process followed a first-order kinetics model and was obviously affected by the initial pH value of medium, incubation temperature and 3-PBA concentration. Under suitable conditions, the half-life (T_(1/2)) of 3-PBA by the strain was 5.889 h. The pathway and mechanism of 3-PBA degradation by the strain were studied by analyzing their degradation intermediates applying GC-MS. And three metabolites of 3-PBA degradation including phenol, catechol and 2-phenoxyphenol were identified. Then, the degradation pathway of 3-PBA by strain SC-1 was inferred according to the variation of metabolites at different incubation times. These results indicated that strain SC-1 has potential applications in the bio-remediation of pyrethroid-contaminated environments.