Central Institute of Brackishwater Aquaculture, 75, Santhome High Road, RA Puram, Chennai, India.
Appl Biochem Biotechnol. 2013 Mar;169(6):1978-92. doi: 10.1007/s12010-013-0109-2. Epub 2013 Jan 26.
In this work, herbivorous fish Mugil cephalus has been cultured to secrete protein rich green slime, which helps nitrifying and oxygen tolerant denitrifying bacteria to grow and colonize. Four strains representing Alcaligenaceae family have been isolated from greenwater system and characterized using biochemical test, fatty acid methyl ester (GC-FAME) analysis, 16S rRNA and functional gene approaches. They were tested for an ability to nitrify ammonia and nitrite aerobically. Two strains showed notable nitrification activity, when grown in a mineral salts medium containing ammonium sulfate and potassium nitrite. Functional gene analysis confirmed the presence of nitrous oxide reductase (nosZ) gene showing that they have an oxygen-tolerant denitrification system. It has been proposed that Alcaligenes faecalis strains heterotrophically nitrify ammonia into nitrite via formation of hydroxyl amine, which is oxidized to nitrous oxide using oxygen or nitrite as electron acceptor. These results provide a possible advantage of having nitrification and denitrification capabilities in the same organism, which plays an important role in biological wastewater system.
在这项工作中，我们培养了草食性鱼类鲻鱼（Mugil cephalus）来分泌富含蛋白质的绿色黏液，这有助于硝化和耐氧反硝化细菌的生长和定植。从绿水系统中分离出了 4 株代表产碱杆菌科的菌株，并通过生化试验、脂肪酸甲酯（GC-FAME）分析、16S rRNA 和功能基因方法进行了表征。测试了它们在含有硫酸铵和亚硝酸钾的无机盐培养基中好氧硝化氨和亚硝酸盐的能力。当在含有硫酸铵和亚硝酸钾的无机盐培养基中生长时，有两株菌株表现出明显的硝化活性。功能基因分析证实存在亚硝酸盐还原酶（nosZ）基因，表明它们具有耐氧反硝化系统。据推测，产碱杆菌属（Alcaligenes）菌株通过形成羟胺将氨异养硝化成亚硝酸盐，然后使用氧或亚硝酸盐作为电子受体将其氧化为亚硝态氮。这些结果为同一生物体中同时具有硝化和反硝化能力提供了可能的优势，这在生物废水处理系统中起着重要作用。
