融合菌株F14降解菲过程中细胞表面性质变化及对土壤中多环芳烃修复研究

发布时间：2018-02-04 18:46

本文关键词： 融合菌株F14 多环芳烃细胞膜微生物降解土壤修复　出处：《中北大学》2017年硕士论文　论文类型：学位论文

【摘要】：多环芳烃(PAHs)具有较大的固水分配系数且生物可利用性偏低,容易对土壤造成大面积污染,使人类活动及生态健康遭受不良影响可能性增大。土壤PAHs污染已成为主要生态问题,PAHs的修复越来越引起人们的重视。融合菌株F14是一株高效降解PAHs的菌株,由假单胞菌和鞘氨醇单胞菌作为亲本,利用原生质体融合技术融合而成。为进一步了解降解菌F14对PAHs代表物菲的降解机制,本文从微生物细胞膜的角度考察了菌株降解菲过程中细胞膜上表面物质的变化情况。利用室内模拟的方法,探讨了融合菌株F14对土壤环境中PAHs代表物菲的降解特性及其影响因子并分析了土壤酶活性以及降解菌的生长情况。分别以校园内清洁土壤和焦化厂厂区内土壤为研究对象,考察菌株F14在PAHs污染土壤中的降解性能,为更好地修复土壤环境中的PAHs污染提供理论依据。主要研究结果如下:(1)细胞膜表面脂多糖、磷脂及脂质过氧化物与降解菲的浓度具有密切的关系,随着菲的浓度增大,磷脂及脂多糖含量也随之增大,当浓度大于150 mg/L时,磷脂含量减小,脂多糖含量继续增大,丙二醛的含量随着菲浓度的增大而增大。融合菌株F14具有较高的表面疏水性,处于对数期以及稳定期的F14表面疏水率达到69.7%,65.2%。这对污染物的去除有很强的促进作用。(2)单因素实验研究了含水率、接种量及添加营养元素对菌株F14降解土壤中的污染物菲的影响情况。结果表明:菌株F14对土壤中菲的降解效果较好,且在接种量为2 m L(浓度0.5 g/mL)、含水率约为60%的条件下最适合菌种生长,C:N:P比例对菌株F14的降解作用影响并不明显。在菲的污染水平为100 mg/kg时,仍有大约30%的菲被降解,说明菌株F14至少能耐受环境中100 mg/kg的污染水平。(3)为探究F14对菲降解过程中生物反应活性,测定土壤中过氧化氢酶、多酚氧化酶(polyphenol oxidase,PPO)和脱氢酶(Dehydrogenase,DHA)的活性,结果表明,土壤中菲的添加刺激了DHA和PPO,对过氧化氢酶活性无刺激作用。此外,融合菌株F14可以在土壤中存活,菌数量随着菲的降解有不同变化。在菲污染土壤中检测到的F14的数量大于无菲土壤中检测到的菌数量。(4)为了探讨菌株F14对焦化土壤中PAHs的微生物修复可行性,应用菌株F14对PAHs工业污染土壤进行修复实验。结果表明,接种F14对PAHs的修复有促进作用,降解60d后,PAHs总降解率平均达到42%;接种F14对2-3环PAHs降解率的提高更加明显,低环PAHs的平均降解率大于空白对照组12个百分点。
[Abstract]:Polycyclic aromatic hydrocarbons (PAHs) have a large solid water partition coefficient and low bioavailability, which can easily pollute the soil in a large area. The possibility of adverse effects on human activities and ecological health is increased. Soil PAHs pollution has become the main ecological problem. More and more attention has been paid to the repair of PAHs. The fusion strain F14 is a highly efficient PAHs degrading strain with Pseudomonas sphingomonas and sphingomonas as parents. In order to further understand the degradation mechanism of PAHs phenanthrene by using protoplast fusion technology. In this paper, the changes of surface matter on the membrane of phenanthrene in the process of degrading phenanthrene were investigated from the point of view of microbial cell membrane. The degradation characteristics and influencing factors of phenanthrene (phenanthrene), a representative of PAHs in soil environment, were studied by the fusion strain F14. The enzyme activity of soil and the growth of degrading bacteria were analyzed. The clean soil and coking plant were used to clean the campus. The soil in this area is the object of study. The degradation of strain F14 in PAHs contaminated soil was investigated to provide theoretical basis for better remediation of PAHs pollution in soil environment. The main results were as follows: 1) lipopolysaccharide on cell membrane. The concentration of phospholipid and lipid peroxide was closely related to the concentration of degrading phenanthrene. The content of phospholipid and lipopolysaccharide also increased with the increase of the concentration of phenanthrene. When the concentration was more than 150 mg/L, the content of phospholipid decreased. The content of lipopolysaccharide continued to increase, and the content of malondialdehyde increased with the increase of phenanthrene concentration. The fusion strain F14 had higher surface hydrophobicity. The surface hydrophobic rate of F14 in logarithmic period and stable period reached 69.7% and 65.2%, which has a strong promoting effect on the removal of pollutants. The results showed that strain F14 had a better effect on the degradation of phenanthrene in soil. Under the condition of inoculation amount of 2 mL (concentration 0.5 g / mL) and moisture content of about 60%, it is most suitable for strain growth. The effect of C: n: P ratio on the degradation of strain F14 was not obvious. When the pollution level of phenanthrene was 100 mg/kg, about 30% of phenanthrene was still degraded. The results showed that strain F14 could at least tolerate the pollution level of 100 mg/kg in the environment. In order to study the bioactivity of F14 in the degradation of phenanthrene, the catalase in soil was determined. The activities of polyphenol oxidase (PPO) and dehydrogenase (DHA) were studied. The addition of phenanthrene in soil stimulated DHA and PPO, but did not stimulate the activity of catalase. In addition, the fusion strain F14 could survive in soil. The amount of F14 detected in phenanthrene contaminated soil was higher than that in non-phenanthrene soil. In order to investigate the feasibility of microbial remediation of PAHs in coking soil by strain F14. Strain F14 was used to repair PAHs contaminated soil. The results showed that inoculation of F14 could promote the restoration of PAHs and degrade it for 60 days. The average degradation rate of PAHs was 42%. The degradation rate of 2-3 ring PAHs was significantly increased by inoculation with F14, and the average degradation rate of low ring PAHs was 12 percentage points higher than that of control group.
【学位授予单位】：中北大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X53;X172

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