高效柴油降解菌的筛选及其对烷烃组分的降解

Isolation of a high-efficient diesel degrading bacteria and its degradation of alkane components of diesel

从东北某油田开采区油污土壤中分离筛选出一株柴油降解菌13-3,经形态观察、16S rRNA鉴定其属于不动杆菌属(Acinetobacter sp.).该菌株在20℃、180r/min的条件下培养7d,可将1g/L的柴油降解88.50%,与其他菌株相比,表现出优秀的柴油降解能力;接种至10g/kg柴油污染土壤中,在20℃、土壤含水量为30%的条件下修复21d,柴油降解率可达71.7%,在柴油污染土壤修复应用中具有较大潜力.根据烷烃底物降解实验,菌株13-3的烷烃利用谱较广,对C_(14)~C_(22)的中长链烷烃均有降解,C_(17)~C_(20)的降解率可达90%以上.环境因素影响实验表明,菌株13-3可在pH值6~9、温度10~30℃、盐度(NaCl)0.5%~3%的范围内生长,在10g/L柴油浓度下仍可获得较好生长,具有良好的环境适应性,有望在复杂的环境条件下发挥其降解性能.通过全基因组测序分析,在菌株13-3的基因组中找到3个烷烃降解关键基因(alkB、almA、ladA),推测其降解烷烃途径为末端氧化.

A diesel degrading bacterial strain 13-3isolated from oil-contaminated soil in an oilfield mining area in Northeast China was identified as Acinetobacter sp.by morphological observation and 16S rRNA.The strain could degrade 88.50%diesel of 1g/L cultured at 20℃ at 180r/min for 7days,which showed excellent diesel degrading ability compared with other strains,and the degradation rate of diesel fuel could reach 71.7%after being inoculated into 10g/kg diesel contaminated soil and remediation at 20℃ and soil moisture content of 30%for 21days,which indicated it had great potential in practical diesel-contaminated soil remediation applications.According to the analysis of GC-MS spectrum and the degrading experiments of different chain length alkane substrates,strain 13-3had a wide alkane utilization spectrum(C_(14)~C_(22)),and the degradation rate of C_(17)~C_(20)could reach more than 90%.The results of environmental factors showed that strain 13-3could grow in the range of pH=6~9,temperature 10~30℃,salinity(NaCl)0.5%~3%,and still had a high concentration of bacterial solution at the initial diesel concentration of 10g/L,which indicated that strain 13-3 had good environmental adaptability and was expected to exert its degradation performance under complex environmental conditions.Through whole-genome sequencing analysis,three key genes(alkB,almA,ladA)were found in the genome of strain 13-3,and the possible degradation pathway of strain 13-3 was speculated to be the terminal oxidation pathway.