两株具有芘降解功能的植物内生细菌的分离筛选及其特性  

Isolation,identification,and performance of two pyrene-degrading endophytic bacteria

作　　者：孙凯[1] 刘娟[1] 李欣[1] 凌婉婷[1] 

机构地区：[1]南京农业大学土壤有机污染控制与修复研究所,南京210095

出　　处：《生态学报》2014年第4期853-861,共9页Acta Ecologica Sinica

基　　金：国家自然科学基金资助项目(41171380;41201501;51278252);中国博士后科学基金资助项目(2011M501246);江苏省自然科学基金资助项目(BK2012370;BK20130030)

摘　　要：从植物体内筛选具有多环芳烃(PAHs)降解功能的内生细菌并定殖于植物体,有望有效地去除植物体内PAHs,从而减低植物污染风险。采用富集培养法,从长期受PAHs污染的植物体内分离筛选出2株能以芘为唯一碳源和能源生长的内生细菌BJ03和BJ05,经形态观察、生理生化特性及16S rDNA序列同源性分析,将2株菌分别鉴定为不动杆菌属(Acinetobacter sp.)和库克氏菌属(Kocuria sp.)。并研究了2株内生细菌对芘的降解能力及环境条件对其降解芘的影响。结果表明,菌株BJ03和BJ05在以浓度为50 mg/L的芘为唯一碳源生长时,于30℃、150 r/min摇床培养15 d后,对芘的降解率分别为65.0%和53.3%。2株菌在pH值(6.0—9.0)、温度(25—40℃)和盐浓度(NaCl含量为0—15 g/L)条件下生长良好,且皆为好氧生长,通气量越大,菌株生长越旺盛,对芘的降解能力越强。添加C、N源可有效促进菌株BJ03和BJ05的生长,加速其对芘的降解速率。当外加C源为蔗糖、N源为酵母膏时,2株菌在30℃摇床培养4 d后,对芘的降解率分别高达71.1%和55.3%。2株菌的细胞表面疏水率最大分别为93.7%和43.9%,对四环素和利福平敏感,而对其它多种抗生素具有较强的抗性。Anthropogenic soil contamination has become a worldwide environmental problem in the past decades. Polycyclic aromatic hydrocarbons （PAHs） are ubiquitous environmental pollutants in soil contaminated with crude oil, creosote, and coal tar. They are generated and dispersed into the environment by fossil fuel combustion, wood treatment processes, automobile exhaust, and waste incineration. The effect and fate of PAHs in soil is of great environmental and human health concern because of the carcinogenic, mutagenic, and teratogenic properties of PAHs. They have been frequently found in soils with high concentrations. PAHs present in soil may be absorbed by plants and translocated from roots to shoots, which is the major pathway for toxic organic substances to reach the food chain/web. Because plants form the basis of human and animal food chains, potentially harmful organic contaminants could find their way into human and animal populations via this route. Clearly, understanding the uptake of PAHs by plant and reducing the plant PAH contamination are essential for assessment of both the PAH exposure to humans and other animal species and the risk represented by PAH-contaminated soils. Endophytic bacteria in plant tissues protect plants from external harsh environments and promote the plant growth. However, there is still little information available heretofore on the endophytic bacteria-influenced uptake and metabolism of PAHs by plants. We proposed that isolation of PAH-degrading endophytic bacteria from plant and colonization of them in the target plants are expected to improve the PAH degradation in plant, thereby reducing the risk of plant PAH contamination. In this study, two pyrene-degrading endophytic bacterial strains, named as BJ03 and BJ05, were isolated from plants grown in PAH-contaminated soils. They were individually identified as Acinetobacter sp. and Kocuria sp. based on the morphology, physiology, and 16S rDNA gene sequence analysis. The degradation characteristics of pyrene by strains BJ03 and

关 键 词：植物内生细菌 多环芳烃 芘 降解 16S RDNA 

分 类 号：S182[农业科学—农业基础科学] Q93[生物学—微生物学]