制革废水中壬基酚聚氧乙烯醚降解菌的分离及特性

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

从长期受壬基酚聚氧乙烯醚污染的制革废水中采集水样,通过富集培养的方法从中筛选到一株可以壬基酚聚氧乙烯醚为唯一碳源生长的降解菌OPQa3。通过形态学特征观察和生理生化试验,结合16S rRNA基因序列分析,初步鉴定菌株OPQa3属于短波单胞菌属Brevundimonas sp.,其16S rRNA基因序列与Brevundimonas diminuta(EU434566.1)的相似性最高(99%)。降解菌OPQa3的生长周期为24 h;以2%的量接种菌株OPQa3,保证最终OD600=0.70,于746 mg/L的壬基酚聚氧乙烯醚培养基中,120 h内的降解率可达84.5%,菌OPQa3生长的最佳温度为30°C,最适pH值在7左右。降解性质粒检测结果表明,控制菌株OPQa3降解壬基酚聚氧乙烯醚的基因位于质粒上。

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 environ-ment;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 re-searches 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 ap-plication of NPnEO by enrichment method.It was preliminarily identified as Brevundimonas sp.ac-cording 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 concentra-tion 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.