Degradation characteristics of bromoamine acid by Sphingomonas sp. FL

A bacterial strain that could degrade bromoamine acid (BAA) as the sole carbon source was isolated. It was identified as Sphingomonas sp. based on 16S rRNA gene sequence analysis and physio-biochemical characteristics. Under the optimal growth conditions, with temperature of 30 degrees C, pH of 7.0, rotating rate of 100 r/min and (NH4)2SO4 as the nitrogen source, the decolorization percentage of BAA (100 mg/L) could reach 99% within 14 h. NaCl of low concentration ( < 2%) facilitated the decolorization, while NaCl of higher concentration (> or = 2%) had inhibition effect. The effect of initial BAA concentration on decolorization could be described by the Haldane model, and the optimal specific decolorization rate of 1.4 h(-1) could be obtained when the initial concentration of BAA was 1393.5 mg/L. The strain could not mineralize BAA completely, and 52.4% of the total organic carbon was removed at the end of the reaction. The analysis of metabolites using GC-MS and HPLC-MS showed that phthalic acid was the metabolic intermediate which could be further degraded through 3, 4-dihydroxybenzoic acid route and serve as the growth substrate, and the end product was estimated to be either 2-amino-3-hydroxy-5-bromobenzenesulfonic acid or 2-amino-4-hydroxy-5-bromobenzenesulfonic acid.