微生物修复汞、铅等重金属污染的研究

发布时间：2018-01-07 08:21

本文关键词：微生物修复汞、铅等重金属污染的研究　出处：《贵州大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着城市化和工业化的加速,土壤的重金属污染问题日趋严重。土壤重金属污染是主要的生态环境问题之一,直接影响到区域生态系统稳定和食品安全,关系到经济尤其是农业的可持续发展和人体健康,因而引起广泛的社会关注。为寻求解决土壤重金属污染的方法,本文从受重金属污染的土壤中筛选具转化重金属能力的微生物,重点筛选可转化Hg、Pb的微生物,并对部分优势菌的转化机理进行初步研究。主要结果如下:1分离到耐汞(100mg/L)真菌68株,耐铅(1000mg/L)真菌97株,耐汞(100mg/L)细菌170株,耐铅(400mg/L)细菌66株。2增加培养基中重金属的含量,复筛得到耐铅(3500mg/L)真菌23株,耐汞(350mg/L)真菌3株;耐铅(800mg/L)细菌3株,耐汞(900mg/L)细菌5株。3将筛选到的高耐性菌株全部进行发酵试验,另外,还选取了部分抗耐性较差的菌株参与试验。检测结果显示真菌⑥ZW15-12、ZW2-5、ZN14-12对铅的转化率分别达到99.36%±0.12%、99.47%±0.3%和99.17%±0.1%;真菌③ZN17-1对汞的转化率达到82.4%±0.40%,真菌③ZT13-4高达92.00%±0.20%。细菌D7-25对铅的转化率达到82.4%±0.2%,细菌④T13-21对铅的转化率高达91.30%±0.3%;细菌W6-10对汞的转化率高达83.3%±0.7%。另外,结果还表明了耐受性高的菌株对重金属转化效果均优于耐受性差的菌株。4筛选出具有高耐受性、高吸附性能的菌株。筛选出具有高耐受性、高吸附性能的菌株。通过形态学、生理生化实验并结合其基因序列构建的系统发育树分析,确定优势菌分别为ZW2-5和⑥ZW15-12:草酸青霉(Penicillium Oxalicum),ZN14-12:微紫青霉菌(Penicillium janthinellum),③ZN17-1:小翅孢壳(Emericellopsis minima),③ZT13-4:镰刀菌(Fusarium striatum),④T13-21和D7-25:节杆菌(Arthrobacter niigatensis),W6-10为蜡状芽孢杆菌(Bacillus cereus)。5在铅离子浓度100mg/L或汞20mg/L的情况下,ZW2-5、ZN14-12、③ZT13-4、③ZN17-1菌株胞外聚合物中蛋白质、糖及胞内谷胱甘肽的含量均比在不含铅和汞情况下高。结果表明优势菌对铅和汞的吸附过程中,既表面吸附,也存在胞内物质的解毒与吸收。6 ZW2-5对铅(100mg/L)的转化率最佳条件为:pH值6和7,接种3ml或4ml,培养9天。③ZT13-4对汞(20mg/L)转化率最佳条件为:pH为7,接种量为4ml,培养9天。④T13-21对铅(50mg/L)的转化最佳条件为:pH为6和7,接种量为3-5ml均可,培养时间为8-9天。W6-10对汞(50mg/L)的转化最佳条件为:pH为6和7,接种量为1-5ml均可,培养时间为8-10天。
[Abstract]:With the acceleration of urbanization and industrialization, heavy metal pollution in soil is becoming more and more serious. Heavy metal pollution in soil is one of the main ecological environmental problems, which directly affects regional ecosystem stability and food safety. It is related to the sustainable development of economy, especially agriculture and human health, so it has caused widespread social concern. In order to find a solution to soil heavy metal pollution. In this paper, microorganisms with the ability to convert heavy metals were screened from soils contaminated by heavy metals. The transformation mechanism of some dominant bacteria was studied. The main results were as follows: 1. 68 strains of mercury-tolerant 100 mg / L) fungi and 97 strains of lead tolerance 1000 mg / L) fungi were isolated. Mercury tolerance 100 mg / L (170 strains) and lead tolerance (400 mg / L) 66 strains (.2) increased the content of heavy metals in the medium. 23 strains of lead tolerant fungi (3500mg / L) and 3 strains of mercury-tolerant fungi (350 mg / L) were obtained. Three strains of lead tolerance (800mg / L) and five strains of mercury-tolerant bacteria (900mg / L) were screened for fermentation. Some strains with poor tolerance were selected to take part in the experiment. The results showed that the fungus 6ZW15-12 was ZW2-5. The conversion rate of ZN14-12 to lead reached 99.36% 卤0.12% 卤0.3% and 99.17% 卤0.1, respectively. The mercury conversion rate of fungi 3ZN17-1 was 82.4% 卤0.40%. Fungi 3ZT13-4 reached 92.00% 卤0.20.The transformation rate of bacteria D7-25 to lead reached 82.4% 卤0.2%. The lead conversion rate of bacteria 4T13-21 was 91.30% 卤0.3. The conversion rate of bacteria W6-10 to mercury was as high as 83.3% 卤0.7. The results also showed that the transformation effect of high tolerance strain was better than that of poor tolerance strain .4. The strains with high tolerance and high adsorption ability were screened out with high tolerance. By morphological, physiological and biochemical experiments and combining with the phylogenetic tree analysis of its gene sequence. The dominant bacteria were ZW2-5 and 6ZW15-12: Penicillium Oxalicum. ZN14-12: Penicillium janthinellum. 3ZN17-1: Emericellopsis minima 3ZT13-4: Fusarium striatum. 4T13-21 and D7-25: Arthrobacter niigatensis. W6-10 is Bacillus cereus).5 with lead ion concentration of 100 mg / L or mercury of 20 mg / L with ZW2-5. Proteins in extracellular polymers of strain ZN14-12O3ZT13-4 and 3ZN17-1. The contents of sugar and intracellular glutathione were higher than those without lead and mercury. The results showed that the adsorption process of lead and mercury by dominant bacteria was both on the surface. The optimum conditions of detoxification and absorption of 6. 6 ZW2-5 of intracellular substance for 100 mg 路L ~ (-1) Pb ~ (2 +) were as follows: ph 6 and 7, inoculation 3 ml or 4 ml. The optimum conditions for 20 mg 路L ~ (-1) conversion of Hg ~ (2 +) were: ph = 7 and inoculation quantity (4ml). The optimum conditions for transformation of 50 mg 路L ~ (-1) Pb ~ (2 +) were as follows: ph: 6 and pH = 7, inoculation amount: 3-5ml. The optimum conditions for transformation of 50 mg 路L ~ (-1) Hg ~ (2 +) with culture time of 8-9 days. W6-10 were as follows: (1) pH 6 and 7, inoculation amount 1-5 ml, culture time 8-10 days.
【学位授予单位】：贵州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X172;X53

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