阿特拉津降解菌Pseudomonas sp. ZXY-1的分离鉴定及降解动力学

Isolation of an atrazine-degrading bacterium (Pseudomonas sp. ZXY-1) and its biodegradation and kinetic studies

摘要:

为深化微生物修复技术在阿特拉津降解中的应用，从受农药污染的土壤中分离出一株高效阿特拉津降解菌株ZXY-1.经鉴定(形态特征、生理生化特征、16s rRNA序列分析)ZXY-1为假单胞菌属(Pseudomonas).研究表明，ZXY-1在11 h内可完全降解初始质量浓度为100 mg/L的阿特拉津，降解效率为9.09 mg/(L·h).同时，实验得到ZXY-1的最适生长条件分别为温度30 ℃、pH 8.0、摇床转速150 r/min、接种量3%.在最适生长条件下，阿特拉津初始质量浓度20~80 mg/L内，菌株ZXY-1的降解符合一级动力学方程；在100~250 mg/L内，菌株ZXY-1的降解符合零级动力学方程.随着初始阿特拉津质量浓度的升高，菌株ZXY-1的生长受到抑制作用，在降解过程中菌株细胞的生长符合Haldane生长抑制模型，其相关动力学参数为μ_max=0.696 h^-1，K_s=98.55 mg/L，K_i=142.6 mg/L.本研究菌株可为含有阿特拉津工农业废水的生物修复提供可行性选择.

Abstract:

A new atrazine-degrading strain named ZXY-1 was isolated in the present study. ZXY-1 was identified as Pseudomonas based on the physio-biochemical characteristics and 16s rRNA gene sequence analysis. The newly isolated strain had a strong ability to biodegrade atrazine of 100 mg/L completely within 11 h, with a degrading rate up to 9.09 mg/(L·h). The optimal conditions for atrazine degradation were captured: temperature 30 ℃, pH 8.0, velocity of shaker 150 r/min and inoculums 3%. Atrazine biodegradation, under the optimum conditions, fitted the first-order kinetic equation when the initial atrazine concentration ranged from 20 mg/L to 80 mg/L, and the zero-order kinetic equation when the initial atrazine concentration ranged from 100 mg/L to 250 mg/L. The kinetic analysis indicated that the strain ZXY-1 cell growth perfectly suited Haldane model with μ_max, K_s and K_i of 0.696 h^-1, 98.55 and 142.6 mg/L, respectively. Overall, this study provided an efficient bacterium and approach that might serve as a viable bioremediation solution to treat the atrazine wastewater.