重金属铜吸附优势菌株的筛选及其特性研究

发布时间：2018-05-07 18:00

  本文选题：气单胞菌 + 重金属铜离子　； 参考：《西南交通大学》2017年硕士论文

【摘要】：随着工业化快速发展及城镇现代化进程加快,我国所面临的重金属污染问题十分严峻,目前我国有将近92%以上的水体受到重金属污染,重金属的超标现象与日俱增。本文利用课题组前期从天然气钻井井场周边污泥和钻井废水中筛选得到的柠檬酸杆菌、丛毛单胞菌、芽孢杆菌、气单胞菌共4株菌株,使用单一菌或两两组合成复合菌群对重金属铜模拟废水进行处理,使用原子吸收分光光度法测定处理前后Cu~(2+)浓度,筛选得到重金属铜吸附优势菌株为气单胞菌。采用分光光度计法测定气单胞菌的耐受性,选择处于对数期的气单胞菌菌体接种到含有不同浓度的Cu~(2+)培养基中,每隔3h测定OD600的值,实验结果表明:气单胞菌对重金属Cu~(2+)的耐受阈值为200mg/L。采用单因素分析法研究气单胞菌吸附重金属铜的吸附行为,确定最优吸附条件为:温度30℃、pH为4、转速为170rpm、菌体投加量为20g/L、初始Cu~(2+)浓度为100mg/L,吸附时间90min,此时吸附率86.25%。进行Cu~(2+)的胁迫实验,在Cu~(2+)胁迫下,气单胞菌菌体内的丙二醛(MDA)含量迅速增加,对气单胞菌造成明显的氧化损伤,同时,培养后期MDA趋于稳定,这一现象推测原因为气单胞菌在生长代谢达到稳定后,存在于细胞膜上的酶能有效的清理体内多余的自由基,防止继续对细胞产生损害。气单胞菌胞外聚合物中存在可以络合Cu~(2+)的分泌物,能使菌体对Cu~(2+)的吸附效率提高,气单胞菌胞外络合能够缓解Cu~(2+)对其微生物细胞体产生的毒性效应,从一方面说也是其重金属耐受性的重要机制。通过本实验对Cu~(2+)吸附优势菌株进行筛选并分析其吸附重金属铜离子的特性,能够为重金属铜离子废水的生物吸附处理技术提供理论依据。
[Abstract]:With the rapid development of industrialization and the acceleration of the modernization of cities and towns, the problem of heavy metal pollution in China is very serious. At present, more than 92% of the water bodies in China are polluted by heavy metals, and the phenomenon of heavy metals exceeding the standard is increasing day by day. In this paper, four strains of citric acid, acanthomonas, Bacillus spp and Aeromonas were screened from sludge and wastewater from natural gas drilling well site in the early stage. The heavy metal copper simulated wastewater was treated by a single bacterium or a combination of two groups of bacteria. The concentration of Cu~(2 before and after treatment was determined by atomic absorption spectrophotometry. The dominant strain of heavy metal copper adsorption was Aeromonas. The tolerance of Aeromonas was determined by spectrophotometer. The bacteria of Aeromonas in logarithmic phase were inoculated into the medium containing different concentrations of Cu~(2. The values of OD600 were measured every 3 hours. The results showed that the tolerance threshold of Aeromonas to heavy metal Cu~(2 was 200 mg / L. The adsorption behavior of heavy metal copper adsorbed by Aeromonas spp. Was studied by single factor analysis. The optimum adsorption conditions were determined as follows: temperature 30 鈩，

本文编号：1857910