一株石油烃降解菌新种Marinobacter sp.PY97S的鉴定

摘要

[目的]为了对1株从黄海沉积物中分离到的石油烃降解菌新种PY97S进行分类学鉴定.[方法]采用16S rRNA基因序列同源性分析、生理生化指标测定、抗生素抗性实验,DNA G+C含量测定、全细胞脂肪酸组成测定、碳源利用实验、呼吸醒测定以及DNA杂交实验等多种方法对该菌株进行鉴定,并通过降解实验测定其对烷烃的利用情况.[结果]菌株PY97S为海杆菌(Marinobacter),革兰氏阴性,接触酶阳性,氧化酶阳性,主要呼吸醌为Q-9.在GenBank中与其16S rRNA基因序列相似度最高的模式株为Marinobacter koreensisDD-M3T(96.93%),两者DNA-DNA同源性仅为46.7%.菌株PY97S的温度生长范围为15℃-35℃(最适为30℃),NaCl浓度生长范围是0-10%(最适为0%),初始pH生长范围为pH 6.0-9.0(最适为初始pH7.0).该菌株可以利用多种糖类和有机酸类的碳源,并对氨苄青霉素、氧哌嗪青霉素等多种抗生素敏感.其DNA G+C含量为48.2 mol%.其主要脂肪酸组成为2-methyl C15∶0(29.97%)、C16∶1ω7c(27.22%)、C12∶0(22.22%)和C16∶1ω9c(5.73%).[结论]菌株PY97S是1株能够降解多种多环芳烃和烷烃的海洋石油烃降解菌新种,具有应用到溢油污染海洋环境生物修复的潜力.%[Objective]To identify and characterize a hydrocarbon-degrading bacterium isolated from the sediment of the Yellow Sea.[Methods]We used 16S rRNA gene sequences based phylogenetic analysis, physiological and biochemical characterization, DNA G + C content assaying, determination of cellular fatty acids, testing of carbon sources and respiratory lipoquinone and experiment of DNA-DNA relatedness.Its capability of degrading aliphatic hydrocarbons in 0NR7a media supplemented with nine n-alkanes, separately, as sole source of carbon and energy was further determined.[Results]The Gram-negative isolate PY97S was a member of the genus Marinobacter, catalase-and oxidase-positive, and with Q-9 as its predominant respiratory lipoquinone.The similarity between its 16S rRNA gene and that of its most closely related type strain in GenBank Marinobacter koreensis DD-M3T was 96.93％ , and their level of DNA relatedness was 46.7％.The appropriate temperature for its growth ranged from 15℃ to 35℃ with the optimum of 30℃ , the appropriate initial acidity from pH 6.0 to 9.5 with the optimum of pH 7.0, and the appropriate salinity ( NaCl) from 0％ to 10％ with the optimum of 0％.It metabolized many carbohydrates and organic acids and was sensitive to diverse antibiotics including ampicillin and piperacillin.The G + C content of its genomic DNA was 48.2 mol％.The major fatty acids were 2-methyl C15∶0 (29.97％), C16∶1ω7c (27.22％), C12∶0 (22.22％) and C16∶1ω9c (5.73％).[Conclusion]The isolate PY97S was identified as a petroleum hydrocarbon-degrading novel species of genus Marinobacter, holding the potential of being applied in the bioremediation of oil spill.