三株轻度嗜盐反硝化菌的分离鉴定和降解特性初探

【作者】 郭艳丽；

【导师】 张培玉；

【作者基本信息】 青岛大学 ， 环境科学， 2009， 硕士

【摘要】 近年来由于工农业的快速发展,排放到水体中的氮素逐年增多,造成严重的水体富营养化,引起水质恶化、湖泊退化,也危害到人体的健康。生物脱氮工艺因具有处理效果好、处理成本低,操作管理方便等优点而得到广泛应用。在石油、化工、海产品加工和养殖等行业中,外排含氮废水大多具有高盐的特点。研究表明,高盐环境下的盐析作用致使微生物的脱氢酶活性降低、导致微生物细胞破裂而死亡,可见高盐浓度对生物脱氮带来不利影响。因此高盐这一特殊生境中反硝化细菌的分离培养和降解特性研究将有助于了解高盐生物脱氮工艺的可行性。本论文在实验室已驯化成熟的活性污泥基础上,采用硝酸钾作为惟一氮源,进行嗜盐反硝化菌的富集、分离和筛选,得到六株具有反硝化性能的嗜盐菌株,根据各菌株的脱氮效果优选降解性能较好的三株菌进行后续试验。通过对三株菌的生理生化试验、16S rDNA测序和同源性分析可得:菌株FX1属于假单胞菌(Pseudomonas sp.),菌株YL-1属于迪茨氏菌(Dietzia sp.),菌株GYL属于盐单胞菌(Halomonas sp.)。考察了盐度、DO、接种量、pH、温度、碳源种类和C/N对三株菌降解性能的影响,得到各菌株的最佳降解条件。研究发现,三株菌在异养硝化培养基中均具有较好的异养硝化效果,在改进的DM培养基中异养硝化效果更好。探讨了菌株FX1的好氧反硝化途径与异养硝化途径相互间的影响,发现该菌株的好氧反硝化作用可以促进异养硝化反应的进行。三株菌既具有异养硝化作用,又具有好氧反硝化作用,可见三株菌可实现同步硝化反硝化(SND),即可以独立完成生物脱氮的全过程。由于三株菌均可耐受一定的盐度,并能实现同步硝化反硝化,因此三株菌对于高盐度废水的处理具有很高的应用价值。更多还原

【Abstract】 In recent years,due to the rapid development of industry and agriculture,the content of nitrate in the wastewater discharged into the water is becoming higher and higher and have caused serious eutrophication,the quality of water depravation and the lake degenerate.Sometimes,the contaminated water will threaten the people health as the water source.The biological nitrogen removal process has many advantages such as cheap in cost, easy in operation,convenient in treatment so it has been widely used in wastewater treatment.In petroleum,chemical,seafood process industry,most of the discharge is hypersaline wastewater.In high-salt environment,the salting-out effect may decrease the microorganisms’ dehydrogenase activity,lead to microbial cells rupture.Sometimes,the salting-out effect even cause death of microbial.So the high salt concentration has a negative impact on the biological nitrogen removal effect.Therefore,the isolation of denitrifying bacteria from hyperhaline habitats will provide a reference value for hyperhaline biological nitrogen removal process.In this paper,we have accomplished the enrichment,islation and screening experiments from the salt-tolerant sludge systems using nitrate as the sole nitrogen source. Six strains of halotolerant denitrifying bacteria were preliminary islated from the activated sludge.According to the degradation characteristics of various strains,we selected three of them for the following tests.According to the morphological observation,physiological biochemical test and sequence analysis of the 16S rDNA,strain FX1 was identified as Pseudomonas sp.;strain YL-1 was identified as Dietzia sp.;strain GYL was identified as Halomonas sp..We have investigated seven different effect factors effecting the degradation characteristics such as salinity,DO,inoculum concentration and so on to get the optimal degradation condition of each strain.The heterotrophic nitrification perfermance of the three bacteria has been found. When these three bacteria were cultured in the DM medium,they have higher nitrogen removal efficiency.And the relationship of aerobic denitrification and heterotrophic nitrification perfermance about FX1 was discussed.The result showed that aerobic denitrification can promote the effect ofheterotrophic nitrification. These three bacteria are aerobic denitrifying bacteria which can simultaneously perform heterotrophic nitrification,so they can realize simultaneous nitrification and denitrification(SND).The three bacteria can achieve SND in hyperhaline environment,so our tests have big application value for nitrogen removal of hyperhaline wastewater.更多还原