Decolorization of bromoamine acid by a newly isolated strain of Sphingomonas xenophaga QYY and its resting cells

A novel strain (designated as QYY) which could grow with bromoamine acid (BAA) as the sole source of carbon, nitrogen and energy was isolated from sludge samples. The strain was identified by 16S rRNA sequencing and physiological-biochemical characteristics. It belonged to proteobacteria alpha subdivision: Sphingomonas xenophaga. For decolorization, the optimal temperature and shaking speed for both growing and resting cells were 30 °C and 150 rpm, respectively. While the most suitable pH was different, 6.5 for growing cells and 8.5 for resting cells. Under the optimal conditions, the removal percent of BAA was over 80-90%. And a conventional substrate-inhibited model-Haldane equation could be applied to describe the decolorization process by resting cells with the concentration range from 10.56 to 114 mg l−1, and the kinetic parameters were as follows: Vmax = 2.53 mg l−1 min−1, Ks = 19.90 mg l−1, Ksi = 91.91 mg l−1. The products were observed by the UV-vis absorbance spectra and the maximum absorption peak in visible area disappeared completely after a short period of incubation.