对硝基酚降解菌的降解特性及动力学

摘要

从某制药厂排污口附近采集的土样中分离筛选得到1株能够以对硝基酚为唯一碳源与能源的降解菌Y9.根据菌株的形态、生理生化鉴定及16S r DNA序列分析初步鉴定,该菌株为恶臭假单胞菌属(Pseudomonas putida).测定了对硝基酚降解过程中亚硝酸盐的产生量.考察了p H和Na Cl浓度对降解率的影响,并对其降解动力学方程进行了拟合分析.同时研究初始接种量与不同浓度对硝基酚降解过程之间的关系.当初始接种量为10％时,菌株Y9在p H 79,Na Cl浓度0.610.0 g/L能够高效降解对硝基酚.当对硝基酚浓度＜350 mg/L时,菌株Y9对对硝基酚的降解符合一级动力学方程.通过对初始接种量的控制,500 mg/L对硝基酚在48 h内的降解率可达21.7％.结果表明,初始接种量的增加可提高菌株Y9对对硝基酚的耐受性及降解率.%A Y9 strain that can utilize p-nitrophenol as the sole source of carbon was isolated from the soil sample of a pharmaceutical plant. Based on the results of morphological observation, physiological and biochemical properties and 16 S r DNA gene sequences, the strain was preliminarily designated as Pseudomonas putida. It was determined that nitrite can be produced with the degradation process of p-nitrophenol. The effects of pH and NaCl concentration on the degradation efficiency were investigated, and the degradation kinetics of p-nitrophenol was analyzed.At the same time, the relationship between inoculum size and degradation process of p-nitrophenol at different concentrations was analyzed by orthogonal experiment. When the inoculum size was 10％, strain Y9 could degrade p-nitrophenol efficiently in a range of pH( 7 ～ 9) and salinity( 0. 6 ～ 10. 0 g/L), When the concentration of p-nitrophenol was lower than 350 mg/L, the degradation of p-nitrophenol was con-sistent with the first-order kinetics. Furthemore, by manipulating the inoculum size, the degradation rate of 500 mg/L p-nitrophenol concentration within 48 h could reach 21. 7％. The data suggest that manipulating inoculum size can increase strain Y9's tolerance to, and degradation of p-nitrophenol.