Isolation and Genomic Analysis of 3-Chlorobenzoate-Degrading Bacteria from Soil.

The compound 3-chlorobenzoate (3-CBA) is a hazardous industrial waste product that can harm human health and the environment. This study investigates the physiological and genetic potential for 3-chlorobenzoate (3-CBA) degradation. Six 3-CBA Gram-negative degraders with different degradation properties belonging to the genera , and were isolated from the soil. The representative strains 19CS4-2 and 19CS9-1 showed higher maximum specific growth rates (, h) than 19C6 and degraded 5 mM 3-CBA within 20-28 h. Two degradation products, chloro-,-muconate and maleylacetate, were detected in all isolates using high-performance liquid chromatography and mass spectrometry. Genomic analyses revealed the presence of and gene clusters in strains 19CS4-2 and 19CS9-1, indicating that they probably metabolized the 3-CBA via the chlorocatechol -cleavage pathway. Strain 19C6 possessed genes, but not genes, suggesting it might have a different chlorocatechol degradation pathway. Putative genes for the metabolism of 3-hydroxybenzoate via gentisate were found only in 19C6, which utilized the compound as a sole carbon source. 19C6 exhibited distinct characteristics from strains 19CS4-2 and 19CS9-1. The results confirm that bacteria can degrade 3-CBA and improve our understanding of how they contribute to environmental 3-CBA biodegradation.