Pseudomonas sp. AOB-7 utilizes PHA granules as a sustained-release carbon source and biofilm carrier for aerobic denitrification of aquaculture water.
Appl Microbiol Biotechnol
; 104(7): 3183-3192, 2020 Apr.
Article
em En
| MEDLINE
| ID: mdl-32055912
ABSTRACT
Nitrate accumulation causes long-time threat to aquatic animals in recirculating aquaculture system (RAS); thus, nitrate removal is also required in RASs. However, the lack of carbon sources makes denitrification difficult to function. Nitrate removal performance of an aerobic denitrifying and extracellular polyhydroxyalkanoate depolymerase-producing bacterium, Pseudomonas sp. AOB-7, using polyhydroxyalkanoate (PHA) granules as a solid sustained-release carbon source in RAS was evaluated. With the initial nitrate-N concentration of 140 mg/L, the high denitrification rates of 0.056 g NO3--N L-1 day-1 and 0.035 g NO3--N L-1 day-1 were achieved in denitrification medium containing poly-ß-hydroxybutyrate (PHB) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), respectively. Significant erosions and pits formed on the surface of the granules made them a good biofilm carrier for AOB-7, and 3-hydroxybutyrate (3-HB) monomer was the major product released to aquatic phase, which was benefit to animals. SEM photos showed that AOB-7 entered and attached on the inside of the PHA particle holes. A 4-week application trial was conducted to reveal the effects of PHB (AOB-7) denitrifying agent and 3-HB produced on growth of zebrafish (Brachydanio rerio) by adding 0.1% (w/v) PHB (AOB-7) denitrifying agent. Result indicated that PHB (AOB-7) denitrifying agent can significantly reduce nitrate-N content in RASs. Compared with the control group, feed coefficient ratio reduced by 18% and weight gain ratio increased by 29% in the PHB (AOB-7) denitrifying agent group. 3-HB monomer produced during the denitrification was speculated to function as a prebiotic and promote zebrafish growth. KEY POINTS ⢠AOB-7 showed a good aerobic denitrifying ability on PHA granules as sustained-release C source. ⢠PHB (AOB-7) denitrifying agent can significantly reduce nitrate content in RAS. ⢠R-3-HB monomer was the major product released to aquatic phase and function as a prebiotic.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Pseudomonas
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Biofilmes
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Poli-Hidroxialcanoatos
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Desnitrificação
Idioma:
En
Revista:
Appl Microbiol Biotechnol
Ano de publicação:
2020
Tipo de documento:
Article