The Nitrogen-Removal Efficiency of a Novel High-Efficiency Salt-Tolerant Aerobic Denitrifier, Halomonas Alkaliphile HRL-9, Isolated from a Seawater Biofilter

Jilong Ren, Chenzheng Wei, Hongjing Ma, Mingyun Dai, Jize Fan, Ying Liu, Yinghai Wu and Rui Han
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Jilong Ren: School of Marine Technology and Environment, Dalian Ocean University, Dalian 116023, China
Chenzheng Wei: School of Marine Technology and Environment, Dalian Ocean University, Dalian 116023, China
Hongjing Ma: School of Marine Technology and Environment, Dalian Ocean University, Dalian 116023, China
Mingyun Dai: School of Marine Technology and Environment, Dalian Ocean University, Dalian 116023, China
Jize Fan: School of Marine Technology and Environment, Dalian Ocean University, Dalian 116023, China
Ying Liu: School of Marine Technology and Environment, Dalian Ocean University, Dalian 116023, China
Yinghai Wu: College of Marine and Civil Engineering, Dalian Ocean University, Dalian 116023, China
Rui Han: School of Marine Technology and Environment, Dalian Ocean University, Dalian 116023, China

IJERPH, 2019, vol. 16, issue 22, 1-13

Abstract: Aerobic denitrification microbes have great potential to solve the problem of NO 3 − -N accumulation in industrialized recirculating aquaculture systems (RASs). A novel salt-tolerant aerobic denitrifier was isolated from a marine recirculating aquaculture system (RAS) and identified as Halomonas alkaliphile HRL-9. Its aerobic denitrification performance in different dissolved oxygen concentrations, temperatures, and C/N ratios was studied. Investigations into nitrogen balance and nitrate reductase genes ( napA and narG ) were also carried out. The results showed that the optimal conditions for nitrate removal were temperature of 30 °C, a shaking speed of 150 rpm, and a C/N ratio of 10. For nitrate nitrogen (NO 3 − -N) (initial concentration 101.8 mg·L −1 ), the sole nitrogen source of the growth of HRL-9, the maximum NO 3 − -N removal efficiency reached 98.0% after 24 h and the maximum total nitrogen removal efficiency was 77.3% after 48 h. Nitrogen balance analysis showed that 21.7% of NO 3 − -N was converted into intracellular nitrogen, 3.3% of NO 3 − -N was converted into other nitrification products (i.e., nitrous nitrogen, ammonium nitrogen, and organic nitrogen), and 74.5% of NO 3 − -N might be converted to gaseous products. The identification of functional genes confirmed the existence of the napA gene in strain HRL-9, but no narG gene was found. These results confirm that the aerobic denitrification strain, Halomonas alkaliphile HRL-9, which has excellent aerobic denitrification abilities, can also help us understand the microbiological mechanism and transformation pathway of aerobic denitrification in RASs.

Keywords: aerobic denitrification; nitrogen-removal; salt-tolerant; napA; narG (search for similar items in EconPapers)
JEL-codes: I I1 I3 Q Q5 (search for similar items in EconPapers)
Date: 2019
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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