一株弯曲固氮菌对多环芳烃的降解特性研究

Degradation Characteristics of Polycyclic Aromatic Hydrocarbons by Azoarcus sp.CE3

微生物修复在多环芳烃(polycyclic aromatic hydrocarbons,PAHs)污染治理方面有着优良特性。为了获得高效降解PAHs的微生物,以荧蒽为唯一碳源进行筛选,分离得到一株高效降解细菌,命名为CE3。经16S rDNA序列分析法鉴定,菌株CE3属于弯曲固氮菌属(Azoarcus),这是首次发现该属菌株对高分子量PAHs具有降解能力。菌株CE3除了能降解荧蒽,还能降解苯、菲、芘、荧蒽、苯并[a]蒽、3-4苯并芘和苯并[b]荧蒽,且对荧蒽和芘的降解率较高,均达到50%以上。分析各种条件对CE3菌降解荧蒽和芘的影响,发现CE3菌能在较广的温度和pH范围降解荧蒽或芘,并且添加酵母提取物、蔗糖和果糖可使CE3菌降解能力提高。

Microbial remediation has excellent characteristics in the control of polycyclic aromatic hydrocarbons(PAHs)pollution.In order to obtain microorganisms that can efficiently degrade PAHs,fluoranthene was used as the only carbon source to screen microorganisms.And then a high-efficiency degrading bacterium named CE3 was isolated.Strain CE3 was identified to belong to Azoarcus genus based on its 16S rDNA sequence analysis.To our knowledge,this is the first report that the strain of the Azoarcus genus has the ability to degrade high molecular weight PAHs.In addition to fluoranthene,strain CE3 also could degrade benzene,phenanthrene,pyrene,fluoranthene,benzo[a]anthracene,benzo[3,4]pyrene and benzo[b]fluoranthene.The degradation rates of fluoranthene and pyrene are more than 50%and higher than the degradation rates of other PAHs.Then,the degradation rates of fluoranthene and pyrene by strain CE3 under various conditions were analyzed in detail by HPLC method.The results showed that Azoarcus sp.CE3 could degrade fluoranthene or pyrene in a wide range of temperature and pH;moreover,the addition of yeast extract,sucrose and fructose to the medium could improve its degradation ability.