The Screening and Identification of Heterotrophic Nitrified Aerobic Denitrifier in the Penaeus Vannamei Boone Aquaculture System without Water Renew

Abstract

The experiments respectively take the artificial substratum (mesh) form the indoor aquaculture systems without water renew of Penaeus vannamei Boone as well as the mature bio-films. Through the complex inoculation on BTB ammonia, nitrite and nitrate medium, screened and obtained the library of the heterotrophic nitrified aerobic denitrifier. Selected 25 single colonies from the bacteria library of two membrane systems to conduct analysis based on the 16s rDNA PCR-RFLP and the results indicated that 50 colonies can be divided into 5 spectral types, in which 2 for the mesh, 3 for the coral sand. After sequencing, the blast comparison shows that all the heterotrophic nitrified aerobic denitrifiers are from the γ-proteobacteria (Gammaproteobacteria), where the bacteria on the mesh belong to the Acinetobacter sp.and Klebsiella sp.; while the bacteria on the coral sand belong to the Pseudomonas sp., Shewanella sp. and Klebsiella sp. According to the analysis on the phylogenetic tree, we know its evolutionary position is basically consistent with the traditional classification. Gram stain analysis indicates that all bacteria are red and belong to the Gram-negative bacteria. The research is of great significance for the selection of the heterotrophic nitrified aerobic denitrifier in the prawn aquaculture systems.