DDT高效降解菌在室内模拟修复中的应用及其降解机理

发布时间：2017-12-26 17:08

本文关键词：DDT高效降解菌在室内模拟修复中的应用及其降解机理　出处：《哈尔滨师范大学》2015年硕士论文　论文类型：学位论文

更多相关文章： DDT 室内模拟降解 固定化 降解途径

【摘要】：本研究以8株具有DDT降解能力的细菌为对象,通过驯化提高其降解率,从中选择降解率最高的菌株研究其降解特性,以正交实验获得各菌株最适降解条件,研究降解途径,分别进行固定化处理,通过正交实验获得最佳降解条件并构建混合菌,模拟自然条件构建室内模拟降解系统,以固定化混合菌株作为研究对象,探究其在室内模拟降解条件下对DDT污染土壤的降解效果。研究结果表明,8菌株的降解率分别由驯化前的31.23%、24.50%、20.68%、35.70%、51.60%、18.40%、40.45%、30.65%提高至35.23%、26.40%、22.90%、40.10%、55.60%、19.50%、46.23%、36.80%。降解率最高的3个菌株为12-2#、12-3#与23#。菌株12-2#的最佳降解条件是:温度32℃、初始pH=7.0、菌体添加量6 mL,最大降解率40.10%;菌株12-3#的最佳降解条件是:温度34℃、初始pH=7.0、菌体添加量8 mL,最大降解率55.60%;菌株23#的最佳降解条件是:温度32℃、初始pH=7.0、菌体添加量6 mL,最大降解率46.23%。3菌株对DDT的降解途径为:好氧条件下,通过2,3-双加氧酶、顺式-2,3-二氢二醇DDT脱氢酶及2,3-二羟基DDT1,2-双加氧酶等的作用,将DDT直接开环,最终生成4-氯苯甲酸。固定化处理使3菌株的降解率分别由40.10%、55.60%、46.23%提高至54.46%、70.07%、61.98%。菌株12-2#、12-3#与23#固定化小球的最佳制备条件分别为:海藻酸钠浓度2%,氯化钙浓度2%,活性炭添加量6 g/L,菌体添加量4 mL(OD600=1.0),交联时间8 h;海藻酸钠浓度3%,氯化钙浓度2%,活性炭添加量6 g/L,菌体添加量4 mL(OD600=1.0),交联时间8 h;海藻酸钠浓度2%,氯化钙浓度2%,活性炭添加量6 g/L,菌体添加量3 mL(OD600=1.0),交联时间8 h时。菌株12-2#、12-3#与23#固定化小球重复利用3次后,降解率未见显著降低(P0.05);低温存储45 d后,降解率仅分别降低4.23%、3.33%与4.52%。混合菌最优构建比例为12-2#:12-3#:23#=1:3:2;最适降解条件为:温度32℃、初始pH=7.0、菌体添加量8 mL,最大降解率为58.43%。混合菌固定化小球的最佳制备条件为:海藻酸钠浓度3%,氯化钙浓度2%,活性炭添加量10 g/L,菌体添加量3mL(OD600=1.0),交联时间8 h;最佳降解条件为:温度32℃、初始pH=7.0、添加量10.0 g,最大降解率70.23%;室内模拟条件下最大降解率49.99%。
[Abstract]:In this study, 8 strains with DDT degrading bacteria, improve the degradation rate through domestication, choose to study the degradation characteristics of the highest rate of degradation from the strains, with the orthogonal experiment to obtain the optimum degradation conditions of the strains, study the degradation pathway, were immobilized by orthogonal experiment, optimal degradation conditions and construct mixed bacteria, simulating the natural conditions of building indoor simulation degradation system with Immobilized Mixed Bacteria as the research object, to explore the effect of simulation on DDT contaminated soil degradation under laboratory condition. The results showed that the degradation rate of 8 strains increased from 31.23%, 24.50%, 20.68%, 35.70%, 51.60%, 18.40%, 40.45%, 30.65% to 35.23%, 26.40%, 26.40%, 26.40%, 26.40%, 26.40%, 40.45%, 30.65%, respectively. The 3 strains with the highest degradation rate were 12-2#, 12-3# and 23#. The optimal degradation conditions of strain 12-2# is: the temperature of 32 DEG C, pH=7.0, initial cell concentration of 6 mL, the maximum degradation rate of 40.10%; the optimal degradation conditions of 12-3# were: the temperature of 34 DEG C, pH=7.0, initial cell concentration of 8 mL, the maximum degradation rate of 55.60%; strain 23# optimal degradation condition is: the temperature of 32 DEG C pH=7.0, the initial cell concentration of 6 mL, the maximum degradation rate of 46.23%. 3, the way of DDT degradation is: under aerobic condition, the 2,3- is directly opened by ring opening of DDT through the action of 2,3- dioxygenase, CIS -2,3- two hydrogen glycol DDT dehydrogenase and 2,3- two hydroxyl DDT1,2- double oxygenase. Finally, 4- chlorobenzoic acid is generated. The degradation rate of 3 strains was increased from 40.10%, 55.60% and 46.23% to 54.46%, 70.07% and 61.98% by immobilized treatment. Preparation conditions of strains 12-2#, 12-3# and 23# were immobilized respectively: 2% sodium alginate concentration, calcium chloride concentration was 2%, the dosage of activated carbon dosage was 6 g/L, 4 mL (OD600=1.0), crosslinking time of 8 h; 3% sodium alginate concentration, calcium chloride concentration was 2%, the dosage of activated carbon 6 g/L, add the amount of mL was 4 (OD600=1.0), crosslinking time of 8 h; 2% sodium alginate concentration, calcium chloride concentration was 2%, the dosage of activated carbon dosage was 6 g/L, 3 mL (OD600=1.0), 8 h crosslinking time. After 3 times of repeated use of strain 12-2#, 12-3# and 23#, the degradation rate was not significantly reduced (P0.05). After storage for 45 d at low temperature, the degradation rate decreased by 4.23%, 3.33% and 4.52%, respectively. The best proportion of mixed bacteria was 12-2#: 12-3#: 23#=1:3:2; the best degradation conditions were: 32 degree temperature, initial pH=7.0, adding 8 mL, and the maximum degradation rate was 58.43%. The optimum preparation conditions for mixed immobilized microorganisms: 3% sodium alginate, calcium chloride concentration was 2%, the dosage of activated carbon was 10 g/L, addition of 3mL (OD600=1.0), crosslinking time of 8 h; the optimal degradation conditions: temperature 32, initial pH=7.0, dosage of 10 g, the maximum degradation rate of 70.23%; the maximum degradation rate of 49.99% under the condition of indoor simulation.
【学位授予单位】：哈尔滨师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X592;X172

【相似文献】