脱氮硫杆菌的分离鉴定和反硝化特性研究

从土壤中分离到1株高活性自养反硝化菌TD,并对其进行了鉴定和硝酸盐还原特性研究.该菌株为革兰氏阴性短杆菌,严格自养.16S rDNA序列分析表明.该菌株与ThiobaciUus denitrificans相似性为99.85%.结合生理生化特性和16S rDNA序列分析,确定菌株TD为脱氮硫杆菌.通过对该菌的生长特性和反硝化特性的研究表明,该菌在初始pH为6.85,32.8℃培养条件下脱氮效果最佳;在初始pH为6.90,29.5℃培养条件下生长最快.该菌生长比较缓慢,没有明显的稳定期,对数生长期阶段的反硝化能力最强,反硝化速率最快,达到了2.245 mg·(L·h)-1,在培养过程中培养基pH值明显下降.较高盐度对该菌株的反硝化活性有抑制作用.该菌株的急性毒性实验结果显示,脱氮硫杆菌对健康鱼体几乎无毒,属于无毒性菌株.

Isolation, Identification and Denitrification Characterization of Thiobacillus denitrificans

In order to investigate the microbial community structures in different membrane bioreactors, total bacterial genomic DNA was extracted from biomass in four MBRs treating different wastewater. The microbial community structures were studied by polymerase chain reaction-denaturing gradient gel electrophoresis(PCR-DGGE) and cloning-sequencing. Furthermore, and the sequences were used for homology analysis and then two phylogenetic trees were constructed. Results indicate that each MBR owns its specific ecological community after a long-term of operation. Influent wastewater composition has a significant impact on total bacterial community structures. Population diversity, which is in the bioreactor fed with more complex components wastewater, is higher than those of other MBRs. The Shannon Index are 0.77 and 0.78. Proteobacteria and Bacillus, which contain 8 OUTs and 2 OUTs, are the climax communities in the investigable MBRs. The profiles of ammonia-oxidizing bacterial community in the four reactors are very similar. There may exist several modes of nitrification and denitrification in MBR because sequences revealed that there exist multitude nitrifying organisms, in which Nitrosomonas are the most predominant, and two denitrifying bacterium (uncultured Achromobacter sp. and uncultured denitrifying bacterium)in reactors.