Cometabolic degradation of p-chloroaniline by the genus Brevibacillus bacteria with extra carbon sources

In this study, we discovered and isolated a new genus Brevibacillus strain from effluent of dyeing and finishing factory containing highly toxic p-chloroanilines (PCA). Based on the morphological, physiological and biochemical characteristics, as well as 16S rDNA sequence, the strain was identified and denominated as Brevibacillus S-618. Co-metabolism effect was found with extra carbon sources including sodium succinate, sodium citrate, ammonium chloride and glucose which can efficiently promote the biodegradation process of PCA. Under the optimal growth conditions at temperature of 30 degrees C, pH(similar to)7 and air-water ratio of 0.3 m(3)/m(3).min, the degradation rate of PCA in a 2 L pilot bioreactor with high concentration of 180 mg/L increased from 86.7% to 100% within 72 h after adding sodium succinate. The release of chloride ions during the growth process of the strain was equivalent to the degradation amount of PCA. Meanwhile, the cleavage pathway of PCA degradation by Brevibacillus S-618 was proposed by analysis of enzyme activities of microorganism and intermediate products in the reaction. Benefiting from excellent degradation ability and unique characters in high pollutant contents, high efficient bioreactor can easily be scale up for industrial application. Our study provides a facile route for cost-effectively and environmental-friendly degrading hazardous chemicals.