N-乙烯基吡咯烷酮降解菌的筛选、降解特性及其竹炭固定化

Isolation and degradation characteristics of a N-vinylpyrrolidone-degrading strain ZF1 and its immobilization on bamboo-based carbon

从活性污泥中分离筛选得到1株N-乙烯基吡咯烷酮(NVP)高效降解菌株ZF1,根据菌株ZF1的形态特征、生理生化特性和16S rRNA基因序列同源性分析,将其初步鉴定为产脲节杆菌(Arthrobacter ureafaciens)。菌株ZF1能以NVP为唯一碳、氮源进行生长,并在60 h内完全降解200 mg·L^(-1)的NVP。菌株ZF1降解NVP的最适环境条件为温度30℃,初始pH 7.0,Na Cl浓度7 g·L^(-1)。为了更好地实现其在实际废水中的应用,将菌株ZF1固定到竹炭上,扫描电镜观察表明ZF1能很好的附着在竹炭表面,且固定菌对NVP的降解效率明显高于游离菌。游离菌和固定菌对NVP的降解均符合一级动力学模型。重复利用5次后,固定菌对NVP的降解率仍能达到98%。

N-vinylpyrrolidone（ NVP） is a common raw material widely used in many industries and belongs to the nitrogen heterocyclic compounds（ NHCs）. Biological degradation was demonstrated as the most cost effective and environmentally friendly way to remove nitrogen heterocyclic pollutants from the environment. In the current study,a highly effective NVP-degrading bacteria,designated ZF1,was isolated from activated sludge. Based on its morphological,physiological,and biochemical properties and 16 S rRNA gene sequence,the strain was identified as Arthrobacter ureafaciens. Strain ZF1 could use NVP as its sole carbon and nitrogen sources,degrading 200mg·L-1NVP to a nondetectable level within 60 h. The optimal environmental conditions for the degradation of NVP were 30 ℃,initial pH of 7. 0,and Na Cl of 7 g·L-1. For its application in real wastewater treatment,strain ZF1 was immobilized onto bamboo-based carbon to enhance the NVP degradation efficiency. SEM observation indicated that strain ZF1 cells were attached well on the surface and pores of the bamboo-based carbon. The degradation kinetics of NVP by free and immobilized cells followed the first-order model. After it was reused 5 times,NVP degradation efficiency was maintained at 98%.