Abstract: The denitrifier Brevibacillus sp. XF-03 could reduce high nitrite concentration(1 000 mg/L)under the condition of high temperature(50℃)by the method of gradient domestication. The effects of carbon source and C/N on growth and denitrification of the denitrifier were optimized by single factor experiments. The results showed that the optimum shortcut denitrification carbon source of Brevibacillus sp. XF- 03 was sodium succinate, optimum C/N ratio 12∶1. Under the optimal condition, the nitrite removal efficiency reached 95.1% within 42 hours when the original concentration of NO- 2-N was 100 mg/L. Nitrite degradation kinetic studies indicated that the strain followed Haldane’s model,and the parameters were: μmax(maximum specific rate)=1.28 h-1, Ks(half-satruration constant)=451.42 mg/L, K i (inhibition constant)= 176.77 mg/L. Nitrite reductase(NIR)activity was preliminary discussed. The NIR specific activity reached 0.279(U/mg protein)at the lag phase of exponential growth.

Key words: Brevibacillus sp.XF-03, High temperature, Shortcut denitrification, Nitrite degradation kinetics, Enzyme activity