Isolation from tannery wastewater and characterization of bacterial strain involved in nonylphenol polyoxyethylene degradation

Abstract:

Nonylphenol polyoxyethylene (NPnEO) is a commonly used nonionic surfactant that can be found in all kinds of detergents and emulsifier. NPnEO has relatively low persistency in the environment; however, the great biological toxicity of NPnEO intermediate products cannot be ignored due to its widespread use. Bioremediation is an effective and economic method to repair the environment that has been polluted by NPnEO. So researchers have paid much attention on the point. Most of these researches focus on the isolation, identification and characterizing bacteria with abilities to degrade NPnEO. In the present study, a bacterial strain OPQa3 capable of utilizing NPnEO as sole carbon source was isolated from water samples collected from tannery waste treatment plant suffered long-time application of NPnEO by enrichment method. It was preliminarily identified as Brevundimonas sp. according to morphological characteristics, physiological-biochemical properties and the similarity analysis of its 16S rRNA gene sequence. The growth period of strain OPQa3 was 24 h. Inoculated 2% of OPQa3 solution, to give a final OD600 of approximately 0.70, to NPnEO solution that initial concentration was 746 mg/L, degradation tests showed that, the degradation rate of strain OPQa3 was 84.5% within 120 h, the optimum temperature is 30 °C while the optimum pH is about 7. At the same time, a plasmid strip was found from strain OPQa3 through plasmid detection. The experiment of plasmid elimination conformed that the plasmid has some relation to the ability of NPnEO degradation which is a degradative plasmid.