Superior performance and mechanism of chlorobenzene degradation by a novel bacterium

A newly isolated strain was identified as Ochrobactrum sp. by 16S rRNA sequence analysis and named as ZJUTCB-1. The strain was able to degrade mono-chlorobenzene (CB) as the sole carbon and energy source under aerobic conditions. This study is the first to report the degradation of CB by the genus Ochrobactrum . The degradation rate of CB reached 170.9 μmol L −1 h −1 , which is at least 6 times higher than the previously reported data. The strain can efficiently degrade CB under a rang of temperatures (30-40 °C) and pH (6.0-7.0) with optimum at 40 °C and pH 7.0. Salt concentration higher than 0.05 mol L −1 remarkably reduced the biodegradation capability. Moreover, true oxic condition was not an essential element for biodegradation given that the CB degradation rate of 210.4 μmol L −1 h −1 was obtained under microaerobic condition. Based on the Haldane kinetic model, the maximum specific growth rate was 0.895 h −1 , which is the highest in ever described CB-degrading strains. According to GC-MS analysis and enzymatic assay, CB was degraded via the meta-cleavage pathway by using 2,3-dioxygenase and 2-chlorophenol as the main intermediates, producing CO 2 and Cl − as the final products. The great performance of CB degradation by Ochrobactrum sp. ZJUTCB-1 provided an alternative for development of more effective and reliable biotreatment process. A newly isolated strain was identified as Ochrobactrum sp. by 16S rRNA sequence analysis and named as ZJUTCB-1.