一株烷烃降解菌的筛选、降解特性及动力学研究

从某炼油厂受石油污染的土壤中分离、筛选得到一株高效烷烃降解菌株C18，经形态观察、生理生化实验和16S rDNA序列分析鉴定其为变形假单胞菌。采用静态摇瓶实验，研究了菌株C18对正十六烷的降解条件和动力学特性，并应用于柴油的降解。菌株降解正十六烷的最适宜条件为温度30～37 ℃、初始pH=7、盐质量分数1%，且在pH=6～9和高盐含量（NaCl质量分数5%）条件下也有良好的降解能力。动力学研究显示，在底物浓度为10～300 mg/L时，获得的米氏方程中，米氏方程常数Km为15.22 mg/L，最大反应速率为11.22 mg/（L·h）。在60 h内，优势菌C18不仅能将浓度为3 000 mg/L的柴油中饱和中长链烷烃高效降解，而且对其中的环烷烃和芳烃也具有良好的降解能力。

ISOLATION OF AN ALKANE-DEGRADATION BACTERIUM AND STUDY ON ITS DEGRADATION PERFORMANCE AND KINETICS

A high effective alkane-degradation bacterial strain C18 was isolated from oil-contaminated soil of a refinery,and it was identified as Pseudomonas plecoglossicida based on its morphological feature,biochemical & physiological characteristics and partial 16S rDNA sequence analysis.The ability of degrading n-hexadecane/diesel and growth kinetics of said strain were studied by shaking flask tests.It was found that the optimum conditions for the growth of strain C18 were under 30—37 ℃,system pH=7 and containing 1% NaCl.Even at pH=6—9 and system containing 5% NaCl,its ability to degrade n-hexadecane was still high.The growth kinetics research showed that when the concentration of n-hexadecane was 10—300 mg/L under optimum conditions,Michaelis equation could be acquired by calculation with Km being 15.22 mg/L and v max being 11.22 mg/(L·h).Under a diesel concentration of 3 000 mg/L,dominant bacterial strain C18 not only could degrade n-alkanes in diesel fuel effectively,but also could well degrade the cyclanes and aromatic hydrocarbons in diesel fuel within 60 h.