ISSN: 0973-7510

E-ISSN: 2581-690X

Research Article | Open Access
Luz Fernanda Dominguez Mendoza1 , Juan Gerardo Quimi Mujica2, Jenny Maribel Risco Cunayque2, Gino Wilmer Aroni Lucana3, Jefferson Javier Intriago Angulo2, Veronica Inיs Sernaquי De la Cruz1, Virna Alexia Cedeסo Escobar1 and Eric Mialhe Matonnier1
1National University of Tumbes, Posgraduate school, Master in Molecular Biotechnology, University City Av. Universitaria S / N – Tumbes., 51 24000, Tumbes, Peru.
2Incabiotec SAC, Molecular biology laboratory, Aquaculture area, 212 Philippines Street, 51 24000, Tumbes, Peru.
3San Luis Gonzaga National University, Faculty of biological Sciences , Department of Biology, Ciudad Universitaria Av. Los Maestros S/N – Ica., 110101, Ica, Peru.
J. Pure Appl. Microbiol., 2019, 13 (4): 1893-1908 | Article Number: 5977
https://doi.org/10.22207/JPAM.13.4.02 | © The Author(s). 2019
Received: 03/12/2019 | Accepted: 23/12/2019 | Published: 28/12/2019
Abstract

The accumulation of nitrogen (-N) is a serious problem in aquaculture as it could lead to mass mortality events of the cultivated species. Chemilitotrophic nitrification is the most recognized in nitrogen removal underestimating the role of heterotrophic nitrifiers. In the present study, the heterotrophic nitrification capacity of 8 bacterial strains isolated from mangrove soil, periphyton and biofilters was evaluated. The strains were grown in heterotrophic nitrification base medium (HNM medium) with three different nitrogen sources, ammonium, nitrite or nitrate at a final concentration of 8 mg L-1, 5 mg L-1 and 80 mg L-1 respectively. The concentration of nitrogen (-N) and OD (600 nm) were determined periodically. Only in 4 strains belonging to the Bacillus genus was the capacity for heterotrophic nitrification and aerobic denitrification observed. Among these strains, SM4 strain presented a good removal profile of ammonium, nitrite and nitrate, achieving an average nitrification efficiency of 98.33 ± 2.89%, 83.67 ± 7.51% and 98.00 ± 0.01% respectively, and a nitrification rate (mg L-1 h-1) of 1.71 ± 0.70, 0.13 ± 0.07 and 0.21 ± 0.06 respectively. The nxrB, nirS, nirK genes in the selected strains were identified by PCR. Additionally, several proteins (enzymes) involved in the nitrogen cycle were identified by proteomic analysis, reporting for the first time the presence of the enzymes ammonia monoxygenase (AMO) and nitrite oxide reductase (NXR) in the genus Bacillus. These findings suggest that the strains studied would have a potential use in the biological removal of nitrogen in aquaculture systems.

Keywords

Heterotrophic nitrification, Bacillus spp, proteomics, aquaculture.

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© The Author(s) 2019. Open Access. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License which permits unrestricted use, sharing, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.