A novel salt-tolerant Micrococcus sp. DUT_AHX capable of degrading nitrobenzene

Abstract

A novel strain of Micrococcus sp. DUT_AHX, which was isolated from the sludge of a nitrobenzene (NB)-manufacturing plant and could utilize NB as the sole carbon source, was identified on the basis of physiological and biochemical tests and 16S ribosomal DNA (rDNA) sequence analysis. It can grow at the temperature up to 40 °C or in the presence of NaCl concentration up to 12 g/L in Luria-Bertani (LB) medium. The optimal degradation conditions are as follows: temperature 37 °C, pH 7.0, and shaking speed 150 r/min. The strain involves a partial reductive pathway due to the release of ammonia and can also utilize 2-aminophenol as the sole carbon source. Furthermore, the enzyme activity tests show that crude extracts of NB-grown strain DUT_AHX mainly contain 2-aminophenol 1, 6-dioxygenase activity. The exploitation of salt-tolerant bacteria will be a remarkable improvement in NB bioremediation and wastewater treatment at high salinity and high temperature.