一株联苯降解菌的筛选及其降解条件研究

Screening of a Biphenyl-Degrading Strain and Determination of the Degradation Conditions

通过选择性富集培养,从济南市南部山区所取的土样中分离得到1株联苯降解菌,实验证明该菌株能以联苯作为惟一的碳源和能源生长,初步命名为LB07,经形态学、生理生化鉴定和16SrRNA基因序列对比分析,确定该菌属于巨大芽胞杆菌。分别研究pH、温度、底物浓度、装液量和培养时间各个单因素对联苯降解率的影响。然后设计正交实验确定菌株降解联苯的最佳优化条件,最佳培养条件为联苯初始质量浓度150mg/L,温度35℃,pH=6.5,装液量为250mL三角瓶装50mL,培养时间10d,菌株LB07降解联苯的性能最好,降解率达到94%。

A biphenyl-degrading bacterial strain was isolated from soil in mountain area of southern Jinan by selective enrichment culture. The strain, named as LB07, was able to use biphenyl as an unique carbon and energy source for growth. It belongs Bacillus megaterium based on the data about morphological, physio-biochemical identification and 16S rRNA sequence analysis. The factors that affecting the strain＇s biphenyl degrading ability such as pH, tempera- ture, initial biphenyl concentration, volume of medium, inoculating dosage and reaction time were determined. The optimal conditions for the biphenyl degradation were definited through orthogonal test. The results showed that the bio- degrading rate could reach the highest as 94% under the conditions of 150 mg/L substrate concentration, 35 ℃ incu- bation temperature, pH 6.5, 50 mL/250 mL medium volume and 10 d reaction time.