Isolation and characterization of aniline-degrading Rhodococcus sp. strain AN5.

A pure culture using aniline as a sole source of carbon and energy was isolated by selective enrichment culturing on a minimum salt medium (MSM) from the Nanjing Chemical Plant, Nanjing, Jiangsu Province, China. An analysis of the 16S rRNA gene sequence and morphological and physiological characteristics showed that this strain was a member of the genus Rhodococcus, and it was designated as strain AN5. Its optimal conditions for aniline biodegradation were 30 degrees C (pH 7.0). Due to the water insolubility of aniline, growth of strain AN5 at various aniline concentrations was studied via spectrophotometry and microcalorimetry in different culture mediums. Strain AN5 not only utilized aniline as its sole carbon and energy resources, but also degraded phenol, benzoic acid and naphthalin. Glucose, peptone and ammonium sulfate, when utilized as its secondary carbon and nitrogen sources, had no active effect on the aniline biodegradation. Such findings would be valuable in the application of strain AN5 to depurate industrial waste water.