【作者】 周燕洁；

【导师】 陆光华；

【作者基本信息】 河海大学 ， 环境科学， 2006， 硕士

【摘要】 氯代芳烃及其衍生物是化工、医药、制革、电子等行业广泛应用的化工原料、有机合成中间体和有机溶剂,大多数在环境中高度持留。这类化合物不仅对水生生物的毒性很强,而且通过自然水体中的微生物降解作用很难消除其影响。目前,相对于其他氯代芳烃类化合物的微生物降解方面所作的大量研究工作,人们对氯代苯胺类化合物的微生物降解研究还很少见报道。因此,研究氯代苯胺类化合物的生物降解特性对保护水资源环境具有重要意义。 作者从南京扬子石化净水一车间曝气池取活性污泥样品,进行分离、培养和驯化,得到了氯代苯胺类化合物的耐受菌,初步鉴定氯代苯胺类耐受菌组成包括黄单胞菌属(Xanthomonas)、产碱杆菌属(Alcaligenes)、假单胞菌属(Pseudomonas)及放线菌科诺卡氏属(Actinomycetaceae nocardia.)。通过细菌生长抑制实验表明,分离得到的复合菌对氯代苯胺的耐受性高于自然水体中(长江)的混合细菌;而且经苯胺和2-氯苯胺驯化后,复合菌对毒物的耐受性进一步提高。 以驯化后的复合菌为降解微生物,采用实验室模拟方法研究了几种氯代苯胺单独存在时的生物降解特性。结果发现,采用苯胺和2-氯苯胺驯化的复合菌能分别以3-氯苯胺、4-氯苯胺及2,4-二氯苯胺为唯一碳源和能源进行生长代谢。但是,相比较而言,用于驯化复合菌的2-氯苯胺比较容易降解,2,4-二氯苯胺的降解率高于3-氯苯胺和4-氯苯胺,4-氯苯胺最难降解。 较之单独存在的情况,2-氯苯胺与2,4-二氯苯胺共存条件下,共存的2,4-二氯苯胺在初期抑制了2-氯苯胺的降解,但是,对2-氯苯胺最终去除率无显著影响。而更易降解的2-氯苯胺的存在使2,4-二氯苯胺的代谢效率明显提高,2,4-二氯苯胺的去除率提高了22%,降解速率常数也提高了50%以上。 以2-氯苯胺为目标污染物,研究化合物暴露浓度、复合菌接种量、水体pH值,添加生长基质等对目标化合物生物降解速率及最终去除率的影响。结果表明,氯代苯胺类化合物的生物降解能适应较广泛的pH值范围,但当pH值降至2.5时,氯代苯胺类化合物的生物降解受到明显的抑制;同时,降低化合物的初始浓度、增加微生物量及添加苯胺生长基质等可以能提高复合菌对氯代苯胺类化合物的去除率。更多还原

【Abstract】 Chlorinated aromatic hydrocarbons and their derivative are chemical materials, intermediate products of organic compounds and organic solvents which are widely applied in industry, such as chemical, medicine, curry, electron and so on. Most of them are persistent in the environment. They are toxic to aquatic organisms, and non-ready to be biodegraded by the microorganisms in nature water. At present, many researches have been done about the biodegradation of chlorinated aromatic hydrocarbons. However, there are few reports about the biodegradability of chloroanilines. It is very important to protect water resources to study the biodegradation characteristic of chloroanilines.Dominant mixed bacteria, which was able to utilize chloroanilines as sole carbon source, was isolated, incubated and domesticated from the activated sludge collected from the returned sludge well hole in the industrial wastewater treatment plant of Yangtse Petrochemical Company. By identification, the dominant mixed bacteria included four kinds of bacteria, which were Xanthomonas, Alcaligenes, Pseudomonas and Actinomycetaceae nocardia. By bacteria growth-inhibition experiment, it has been shown that the isolated mixed bacteria were more tolerant to chloroanilines than the bacteria from nature water (Yangtze River), and after the domestication with aniline and 2-chloroaniline selective medium, the toleration of dominant mixed bacteria was improved evidently.The biodegradability to the chloroanilines used the dominant mixed bacteria as degradation microorganism by laboratory simulation method. The result showed that dominant mixed bacteria domesticated with aniline and 2-chloroaniline was able to utilize 3- chloroaniline, 4- chloroaniline and 2,4- dichloroaniline as sole carbon source and energy source. However, 2-chloroaniline, which was used to domesticate the dominant mixed bacteria, was the most easily to be biodegraded, while 4-chloroaniline was the most difficultly to be biodegraded. The biodegradation rate of 2,4- dichloroaniline is higher than 3- chloroaniline and 4- chloroaniline.Compared with existence lonely, when 2-chloroaniline and 2,4-dichloroaniline co-existing, 2,4-dichloroaniline would inhibit the biodegradation of 2-chloroaniline in the initial stage. But it would not have a notable effect on the final biodegradation rate of 2-chloroaniline. However, the biodegradation rate of 2,4-dichloroaniline was improved obviously because of the existence of 2-chloroaniline which was moreeasily degraded. The biodegradation rate of 2,4-dichloroaniline was improved 22%, and its biodegradation rate constant was improved more than 50%.Using 2-chloroaniline as object pollutant, we researched the effects of condition factors to object compound’s biodegradation rate and ultimate degreased rate, such as the exposure concentration of compound, the mixed bacteria’s inoculum size, the water’s pH value and appending growth matrix. The experimental results showed that the dominant mixed bacteria could adapt the extensive pH value. However, the biodegradation would be obviously restrained when pH value was below 2.5. Besides, decreasing initial concentration, increasing bacterial concentration and appending growth matrix could improve the biodegradation rate.更多还原