污染土壤中菲降解菌的分离鉴定及其降解能力

Isolation,Identification and Degradation Ability of Phenanthrene-Degrading Bacteria from Contaminated Soils

利用水-硅油双相系统富集培养和平板升华方法，从被多环芳烃（PAHs）污染的表层土壤中筛选分离得到10株能利用菲为唯一碳源和能源生长的菌株。这10株菌在无机盐培养基中10d内对初始质量浓度为50mg／L的菲的去除率为27．6％～55．3％，其中一些菌株混合可提高或降低菲的去除率；通过形态观察、生理生化指标测定及分子生物学分析（16SrDNA）等方法对其中3株具有较高降解能力的菌株（分别定名为PE0402—5，PE0902—1和PE1501—1）进行鉴定．这3株菌的16SrDNA序列分别与Gordonia，Mycobacterium以及Azospirillum 3个属的相似性达100％，99％和99％．结合分离菌株的形态、生理生化特征和16SrDNA基因序列的分析结果，初步鉴定菌株PE0402—5为戈登氏菌（Gordonia sp．）。PE0902—1为分枝杆菌（Mycobacterium sp．）。PE1501—1为固氮螺菌（Azospirillum sp．）．

Ten bacterial strains capable of utilizing phenanthrene as a sole source of carbon and energy for growth were isolated from surface soils contaminated by polycyclic aromatic hydrocarbons （PAHs） through the selective enrichment technique with water silicon oil biphase system and the sublimate-plate method. These strains can degrade 27.6 %-55.3 % of phenanthrene with an initial mass concentration of 50 mg/L in mineral media within 10 days. Mixed microorganisms from some of the 10 isolates can either increase or decrease the degradation rate of phenanthrene. Three stains, designated as PE0402-5, PE0902-1 and PE1501-1, were identified according to their morphological, physiological and biochemical characteristics. The 16S rDNA sequences of PE0402-5, PE0902-1 and PE1501-1 were highly similar to those of C, ordonia sp., Mycobacterium sp. and Azospirillum sp., with sequence similarity up to 100%, 99% and 99%, respectively. The results showed that the three phenanthrene-degrading bacteria PE0402-5, PE0902-1 and PE1501-1, belonged to the genera Gordon/a, Mycobacterium and Azospirillum, respectively.