一株高效降解中长链烷烃菌株的分离鉴定及其降解特性研究

Isolation and Characterization of a Novel Medium-Long Alkane-Degrading Strain

摘要: 从南充市炼油厂被石油污染土壤中分离到一株中长链烷烃降解菌TY12。采用形态学观察、生理生化指标测定、抗生素抗性实验、16S rRNA基因序列同源性分析等多种方法对该菌株进行鉴定。菌株为Acinetobacter beijerinckii，革兰氏阴性，短杆状，无荚膜，无芽孢，接触酶阳性，氧化酶阴性，菌体大小为0.9~1.6 μm × 1.5~2.5 μm；对新霉素、氯霉素、卡拉霉素等14种抗生素敏感，而对四环素、阿莫西林、氨苄西林耐药；在GenBank中与其16S rRNA基因序列相似度最高的模式株分别为Acinetobacter beijerinckii CCM7266 (AJ626712)、Acinetobacter beijerinckii LMH6214 (AJ303013)，相似性为100%。研究表明，以工业乙醇为唯一碳源的无机盐培养基培养种子最适宜；其最适温度和pH分别为30℃和7.0，无水乙醇最适加入量为0.7%，最适酵母粉浓度为0.025 g/L。在初始正十二烷浓度为1%(W/V)培养基中接入1%种子液，于30℃、180 r/min震荡培养36 h，正十二烷降解率可达92%；菌株对正构烷烃的降解范围较宽，能以C12~C32的正构烷烃为唯一碳源和能源生长。该菌是一株能够降解中长链烷烃的不动杆菌新种，具有应用到石油污染修复的潜力。

Abstract: A strain of medium-long chain n-alkanes degrading strain TY12 was screened from petroleum-contaminated soils of Nanchong oil refinery. We adopted several phenotypic and genotypical methods, such as morphological, physical and biochemical characteristics, antibiotic susceptivities, 16S rRNA gene sequences based phylogenetic analysis, to outline the basic biological characteristics and determinate the phylogenetic position. The Gram-negative isolate TY12 was a member of the genus Acinetobacter, short rods, no capsules, no endospores, catalase-positive, oxidase-negative, 0.9 - 1.6 μm in diameter and 1.5 - 2.5 μm in length; TY12 was susceptible to 14 kinds of tested antibiotics but resistant to Tetracycline, Amoxicillin, Ampicillin; The similarity between its 16S rRNA gene and that of its most closely related type strain in GenBank Acinetobacter beijerinckii CCM7266 (AJ626712), Acinetobacter beijerinckii LΜH6214 (AJ303013) were 100%. The optimal temperature and pH for the strain utilizing industrial ethanol were 30˚C and 7.0, and the optimal concentration of ethanol and concentration of yeast extract were 0.7% and 0.025 g/L, respectively. The n-dodecane degradation was 92% after the strain was growing on in hydrocarbon degradation medium with 1% (W/V) of n-dodecane at 30˚C and 180 r/min for 36 h. The strain could degrade a large range of n-alkanes with chain length C12 - C32. It has potential in bioremediation of oil contaminated environment.