翅碱蓬根系降油细菌的筛选及其生长特性研究

为建立适用于沿海滩涂石油污染的翅碱蓬-细菌复合修复技术,对翅碱蓬Suaeda heteroptera Kitag根系及其土壤进行常规细菌分离,并采用柴油为唯一碳源的平板,从中筛选具有降油性能的菌株并对筛选的菌株进行降油性能测定,研究其在不同作用时间(3、5、7 d)时对柴油的原始降解率,选择在3个时间段中降油性能均较高的菌株作为目的菌进行形态学观察、生理生化特征和16S r DNA序列分析,测定其生长特性。结果表明:试验中共分离纯化出28株细菌,其中具有降油性能的细菌有7株,编号分别为S1、G3、G4、G9、G10、G11、G12;7株细菌对柴油的原始降解率,作用3 d时分别为34.21%、3.68%、18.40%、18.95%、0.52%、9.47%、21.05%,作用5 d时分别为44.06%、3.19%、23.90%、24.70%、31.47%、25.90%、46.22%,作用7 d时分别为41.09%、1.49%、14.36%、28.22%、14.36%、29.70%、31.68%;S1、G11和G12菌株对柴油具有较高降解率;S1属微杆菌属Microbacterium,与Microbacterium saperdate的相似性为98.7%,G11和G12均属于刘志恒菌属Zhihengliuella,与Zhihengliuella halotolerans的相似性均为99.8%,3株菌的最适生长温度范围均为15~30℃,最适生长盐度分别为0、20、20,最适生长p H分别为5、7和7。

Screening and growth of oil-degrading bacteria from roots of seepweed herb Suaeda heteroptera Kitag

In this study, culturable bacteria were isolated from soil and roots of seepweed herb Suaeda heteroptera from which the oil-degrading strains were screened using plates containing diesel oil as the sole carbon source in or-der to provide dominant strains for the establishment of practical composite technology using Suaeda heteroptera-bacteria carrier to repair the oil pollution in coastal beach. During the experiment, the original degradation rates of diesel were measured by the oil-degrading strains, through which the strains with high degradation rates were se-lected as the target strains in order to investigate their degradation of diesel and growth in 3, 5, and 7 d. The strains with excellent degradation property were identified by morphological observation and analysis of 16 S rDNA sequences and physio-biochemical characteristics. A total of 28 strains were isolated, in which 7 strains numbered as S1, G3, G4, G9, G10, G11 and G12 were tested to have oil degrading ability. It was found that the original diesel degradation rate was 34 . 21% in S1 , 3 . 68% in G3 , 18 . 40% in G4 , 18 . 95% in G9 , 0 . 52% in G10 , 9 . 47% in G11 , and 21 . 05% in G12 in 3 d;44 . 06%, 3 . 19%, 23 . 90%, 24 . 70%, 31 . 47%, 25 . 90%, and 46. 22% at 5 d, and 41. 09%, 1. 49%, 14. 36%, 28. 22%, 14. 36%, 29. 70%, and 31. 68% at 7 d, S1, G11 and G12 showing the excellent degradation. S1 shared the maximal 16S rRNA gene sequence similarity with the type strain Microbacterium saperdate (98. 7%), was affiliated with the genus Microbacterium. G11 and G12 which exhibited the highest 16 S rRNA gene sequence similarity with the type strains of Zhihengliuella halotolerans (99. 8%) were both affiliated with the genus Zhihengliuella. The suitable growth temperature for S1, G11 and G12 was 15-30 ℃, the optimal salinity for their growth were 0, 20 and 20,and the optimal pH 5, 7 and 7, for growth respectively.