南四湖光合细菌的分离鉴定及对水体净化的初步研究

发布时间：2018-03-31 02:25

  本文选题：南四湖　切入点：光合细菌　出处：《曲阜师范大学》2015年硕士论文

【摘要】：南四湖是山东省内最大的淡水湖,在经济发展和水资源利用中具有重要的作用,但近年来周围地区经济的高速发展及人为因素,湿地生态系统遭到严重破坏,水体出现富营养化状态。而光合细菌具有特殊的生理生化性质,能够降解水体中的污染物,因此筛选出具有净化水质功能的光合细菌对于改善南四湖目前的现状具有重要的作用。本课题从南四湖底泥中筛选分离出了22株光合细菌,选取具有代表性特征其中两株菌GH-5和GH-12作为研究对象,分别进行鉴定,优化了培养条件和改良了培养基配方,初步研究了这两株菌对养殖污水中总氮、总磷和COD的降解情况。通过形态学鉴定、生理生化鉴定及分子鉴定等一系列鉴定实验最后确定GH-5属于紫色非硫细菌科、红细菌属、荚膜红细菌Rhodobacter capsulatus,GH-12属于紫色非硫细菌科、红细菌属、球形红细菌Rhodobacter sphaeroides。通过对GH-5和GH-12培养条件的研究,得出GH-5的最适培养条件为:接种量为5%、培养温度为25℃、初始pH为7.0;GH-12的最佳培养条件为:接种量为5%、培养温度为30℃、初始pH为8.0。通过对ATYP培养基进行改良,得出了最优培养基配方,其中菌株GH-5的最佳培养基配方为NaHCO3含量为2000mg/L、酵母膏含量为1000mg/L、乙酸钠含量为1000mg/L;菌株GH-12的最佳培养基配方为NaHCO3含量为1500mg/L、酵母膏含量为1000mg/L、乙酸钠含量为2000mg/L。GH-5和GH-12均能够对养殖污水进行净化,其中菌株GH-5在光照微好氧、温度为25℃、菌体添加量为2mg/L时对污水的降解效果最好,总氮、总磷和COD的去除率分别为66.8%、58.1%、62.7%;菌株GH-12在光照微好氧、温度为30℃、菌体添加量为5mg/L时对污水的降解效果最好,总氮、总磷和COD的去除率分别为62.1%、59.2%、60.7%。并且两种菌株混合加入对三个指标的降解效果比单一菌株的降解效果好,当GH-5与GH-12的添加比例为2:1时,对污水的降解效果是最好的,总氮、总磷和COD的去除率分别为68.2%、58.8%、64.3%。研究结果表明,从南四湖底泥中筛选出的光合细菌具有净化水质的功能,为南四湖微生物多样性和生态环境保护提供了理论依据。
[Abstract]:Nansihu Lake, the largest freshwater lake in Shandong Province, plays an important role in economic development and water resources utilization. However, in recent years, the wetland ecosystem has been seriously damaged by the rapid economic development and human factors in the surrounding areas. The photosynthetic bacteria have special physiological and biochemical properties, which can degrade the pollutants in the water body. Therefore, the screening of photosynthetic bacteria with the function of purifying water quality plays an important role in improving the present situation of Nansihu Lake. In this paper, 22 photosynthetic bacteria strains were isolated from the sediment of Nansihu Lake. Two strains of bacteria, GH-5 and GH-12, were selected as the research objects. The culture conditions were optimized and the medium formulation was improved. The total nitrogen of the two strains in the culture wastewater was preliminarily studied. The degradation of total phosphorus and COD. A series of identification experiments, such as morphological identification, physiological and biochemical identification and molecular identification, finally confirmed that GH-5 belongs to the purple non-sulfur bacteria family, the red bacteria genus Rhodobacter capsulatusu GH-12 belongs to the purple non-sulfur bacteria family. Rhodobacter sphaeroides.Through the study of GH-5 and GH-12 culture conditions, the optimum culture conditions of GH-5 were obtained as follows: inoculation amount was 5, culture temperature was 25 鈩，

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