【作者】 于波；

【导师】 许平；

【作者基本信息】 山东大学 ， 微生物学， 2006， 博士

【摘要】 杂环化合物是指具有环状结构，并且除碳氢原子外，至少还含有一个杂原子的化合物。本文研究的对象主要是含有硫、氮、氧三类杂原子的孤对电子杂环化合物。这些杂环化合物是严重的污染源，化石燃料中的含硫、含氮化合物是在燃烧过程释放出大量的硫氧化物和氮氧化物，是酸雨的成因之一，对环境造成了严重的污染。随着人类社会的发展，能源的消耗与日俱增，这些化合物造成的污染也越来越严重。生物处理方法由于具有操作条件温和、费用低、对环境造成的二次污染少而受到越来越多的重视。二苯并噻吩(Dibenzothiophene，DBT)是化石燃料中含有的一种典型的有机硫化合物，使用传统的加氢脱硫(Hydrodesulfurization，HDS)难以去除，因此选择DBT作为微生物脱有机硫反应的模式化合物。石油中的含氮化合物主要是咔唑(Carbazole，CA)的各种烷基衍生物，所以生物脱氮的研究是以CA为模式化合物。二苯并呋喃(Dibenzofuran，DBF)是研究二恶英类(dioxin-like)氧杂环环境污染物生物降解的模式化合物。 本工作使用实验室前期分离出来的一株降解DBT的菌株XP为研究对象。菌株XP为常温菌株，可以在30℃左右降解含硫化合物。对XP菌株进行了菌种鉴定，XP菌落生长初期形成短的分枝菌丝体，然后分化成球菌及棒杆菌的形态；菌落有光泽，从奶白色逐渐变为粉红色；XP菌株的分枝菌酸属于红球菌分枝菌酸；脂肪酸类型为无分支，含有饱和及不饱和脂肪酸，同时还含有结核菌脂酸，与数据库中的红平红球菌脂肪酸类型有86.5％的同源性；XP菌株的riboprint模式与模式菌株Rhodococcus erythropolis DSM 43066~T相似；XP菌株的16S rDNA序列在诊断区(1-500个碱基)与模式菌株Rhodococcus erythropolis DSM 43066~T的16S rDNA序列100％的同源。通过上述常规的形态学、化学分析法(包括脂肪酸、分枝菌酸分析)和分子生物学结果(Riboprint pattern和16S rDNA序列的比对)，最终确定XP菌株属于红平红球菌，命名为Rhodococcus erythropolis XP。 红平红球菌(Rhodococcus erythropolis)XP可以利用各种硫源，包括部分甲基噻吩、甲基苯并噻吩及全部测试的二苯并噻吩类化合物为唯一硫源生长。通过更多还原

【Abstract】 Sulfur, nitrogen, and oxygen heterocycles (SNO-heterocycles) with lone electron pair are polycyclic aromatic compounds containing one or more S-, N-, and/or O-atoms in five or six membered rings. SNO-heterocycles and their degradation products have been detected to be toxic and mutagenic. Additionally, sulfur and nitrogen oxides released from fossil fuel combustion contribute to acid rain and air pollution. At the present time, petroleum refining is mainly based on the use of physicochemical processes such as distillation and chemical catalysis that operate under severe conditions, i.e. high temperatures and pressures. Such processes are energetically costly and highly contaminating. "Biorefining", in contrast, operates at ambient temperature and pressure and is endowed with a high selectivity, resulting in decreased energetic costs, low emissions and no generation of undesirable by-products, so it is thought to be an interesting complement for the development of new petroleum refining processes. S-heterocycles, dibenzothiophene (DBT) and N-heterocycles, carbazole (CA) are the main heterocyclic structures in petroleum. Therefore, DBT and CA are widely used as model compounds for the study of the biodegradation of polycyclic aromatic sulfur- and nitrogen-containing hydrocarbons, respectively. Additionally, O-heterocyclic compound, dibenzofuran (DBF) was a model compound to study the biodegradation of the ’dioxin-like’ compounds and its chlorinated derivatives, which are of great environmental concern.This work focused on a mesophilic strain isolated in our laboratory previously. The strain XP was capable of degrading DBT at 30°C. Strain XP was previously identified as a Rhodococcus species and further identification was performed in Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH (DSMZ). Strain XP was an aerobic, gram-positive bacterium. The cells were shown to be short branched hyphae, which disintegrated to rod and coccus-like elements. Colonies were shiny dissolving, cream to pink. The mycolic acid pattern was更多还原