ISOLATION AND SELECTION OF LOCAL NITRIFYING BACTERIA WITH HIGH ACTIVITY IN QUANG NINH, HAI PHONG

Abstract

Ammonia in the aquatic environment is one major problem that leads to damage in aquaculture. Ammonia is toxic to all vertebrates causing convulsions, coma and death. The isolation and selection of the local nitrifying bacteria are expected as a solution to reduce ammonia concentration and improve water quality. This study aimed to isolate and identify bacteria in Quang Ninh, Hai Phong provice as the candidate to reduce ammonia. Bacteria were isolated in a selected liquid enrichment medium and identified by biochemical tests also molecular analysis of the 16S rRNA gene sequence. The result was isolated and selected eight nitrifying bacteria that have a high potential for application in aquaculture water treatment. By BLAST software on NCBI, 16S rRNA gene sequences of isolated nitrate bacteria were compared with bacterial strains on GenBank.The results showed that the identification was over 96.71% compared with the sequences on the Genbank. Nitrifying bacteria species were isolated include: Nitrosomonas marina, Nitrosomonas nitrosa, Nitrosomonas aesturii... in which, there are 2 characteristic species of bacteria, Nitrosomonas europaea and Nitrobacter Winogradsky.