【作者】 蒋丽娟；

【导师】 尹大强； 杨柳燕；

【作者基本信息】 南京大学 ， 环境科学， 2011， 博士

【摘要】 1、通过室内模拟试验,研究孔雀石绿在养殖水体沉积物中的降解行为,结果显示孔雀石绿降解半衰期在12.9天-50.34天之间。降解过程中产生无色孔雀石绿,且消除时间比孔雀石绿消除时间长。沉积物中孔雀石绿浓度和温度均对孔雀石绿降解有影响,浓度上升,降解速率降低；温度上升,降解速率加快。沉积物孔雀石绿降解中微生物降解作用明显,光降解作用影响不明显。呋喃唑酮在沉积物中降解迅速,半衰期为33.39h。呋喃唑酮降解中会产生代谢产物AOZ,且在沉积物中消除时间长。AOZ在沉积物中降解半衰期为22.5天。2、从受孔雀石绿污染的养殖水体底泥中驯化分离到MJl菌株能有效降解孔雀石绿,经鉴定为假单胞菌(Pseudomonas sp.),该菌对无色孔雀石绿也具有降解能力。菌株MJl对孔雀石绿的24h和72h降解率为83.3%和93.6%,降解过程中有少量无色孔雀石绿代谢产物的产生。对5mg/L无色孔雀石绿的24h和72h降解率为72.9%和84.4%,降解效果相交孔雀石绿要略差。孔雀石绿浓度在低于10mg/L时,菌株MJl对孔雀石绿降解率都超过90%。在30-35℃降解率最佳,均能超过90%；pH7.0-9.0范围比较适合菌株对MG降解,pH7.0为最佳降解PH值。HPLC-MS对代谢产物进行初步研究分析,得到九个产物,并推断可能存在的裂苯环降解途径。3、从多次使用过呋喃唑酮的鱼塘底泥中富集驯化分离筛选得到菌株F1和F5对AOZ的降解效果较好,72h降解率分别为85.6%和89.7%。通过生理生化特征及16SrDNA测序结果鉴定F1菌株为苍白杆菌(Ochrobacterum sp.),F5为铜绿假单胞菌(Pseudomonas aeruginosa)。菌株F1对5mg／L的AOZ在20-40℃降解率均大于90%,适应温度范围宽,而菌株F5的最适温度在30-35℃。菌株F1适合的pH范围是7.0-8.0,而F5则是6.0-8.0,F5适应pH范围更宽。4、固定菌制备的最佳条件为：CaC12浓度5%,海藻酸钠浓度2%,胶联时间16h、包菌量600mg/kg。菌株MJ1和M3固定化后降解能力均有提高,MJl降解能力优于M3。MJl固定化后适应pH能力增强。混合固定菌对不同浓度孔雀石绿的底泥均有降解,且对低浓度(<1.0μg／g干重)底泥降解效果更好。固定菌的加入使得孔雀石绿降解半衰期缩短,表明固定菌对孔雀石绿的降解是有效的。适当增加固定菌的投菌量可提高降解速率和降解率,但这不是无限的。自然光照对孔雀石绿有一定降解作用,固定菌和自然光照联合作用后可以大大提高降解率,其中对降解起主要作用的是固定菌。5、大型溞急性毒性试验表明菌株MJ1和M3对大型溞的LC50均大于500mg/L。斑马鱼急性毒性试验表明两株菌对斑马鱼的LC50均大于500mg/L。1000mg/L高剂量组下,两株菌对鲫鱼抗氧化防御系统酶活未出现影响。表明两株菌具有相当的安全性。更多还原

【Abstract】 1. The study of the degradation of the malachite green (MG) in the aquacultural sediment showed that the half-life of MG was from12.9days to50.34days. Leuomalachite green (LMG) was generate during the degradation. The elumination of LMG was slower than MG The decrease of initial concentration of MG and the increase of the temperature is benefit to the degradation of MG. The microbiodegradation was play an important role in the degradation, while the photodegradation was not important. The half-life of furazolidone in the sediment was33.39h.. The metabolite,3-amino-2-oxazolidone (AOZ), was detected during degradation. The half-life of AOZ was22.5days.2. Strain MJ1isolated from MG polluted fishery pond can degrada MG effectivly and was identified as Pseudomonas sp. This strain can also degrade LMG The24h and72h degradation rate of MG was8.33%and93.6%respectivly. The24h and72h degradation rate of LMG was72.9.%and84.4%respectivly. Degrdation ratio was more than90%if the initial concentration of MG was under10mg/L. The optimal degrdation temperature was30-35℃. The optimal degradation pH range was7.0-9.0. Nine main transformation products of MG degradated by strain MJ1were identified by liquid chromatography mass spectrometry. The possible metabolic pathway of degradation of MG by strain MJ1was cleavage of one benzene ring.3. Strain F1and F5isolated from furazolidone polluted fishery pond can degrade AOZ efficiantly. Degradation ratio of strain F1and F5was85.6%and89.7%respectivly. Strain F1and F5were identified as Ochrobacterum sp. and Pseudomonas aeruginosa. The optimal condition of strain F1was20-40℃and pH7.0-8.0. the optimal condition of strain F5were30-35℃and pH6.0-8.04. Strain MJ1(Pseudomonas sp.) and M3(Pantoea sp.) were immobilized by sodium alginate. Optimal immobilizing condition was:5%CaCl2,2%sodium alginate,16h calsifying time and600mg/kg bacterial biomass. Degradation ratio of strain MJ1and M3was increased after immobilization. The optimal condition of immobilzed strain MJ1was pH6.0-9.0and30-35℃, while strain M3was pH5.0-9.0and25-30℃. Mixed immobilized bacteria MJ1and M3can degrade MG in the sediment. The degaradation half-life of MG in the sediment was shortened if adding immobilized bacteria. Adding the biomass of the immobilized bacteria can increase the degradation rate and ratio. Sunlight can degrade some of MG in the sediment.5. Aute toxicity test of Daphnia magna showed that the LC50of strain MJ1and M3were both more than500mg/L. Aute toxicity test of Brachydanio rerio showed that the LC50of strain MJ1and M3were both more than500mg/L. strain MJ1and M3had no oxidative stress on Carassius auratus.更多还原