Influence of metal ions and organic carbons on denitrification activity of the halotolerant bacterium, Paracoccus pantotrophus P16 a strain from shrimp pond

Pintathong, Punyawatt; Richardson, David J.; Spiro, Stephen; Choorit, Wanna

doi:10.2225/vol12-issue2-fulltext-12

Cited by 20 publications

(18 citation statements)

References 49 publications

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“…The production of Fe(III)‐chelating and Fe(III)‐mobilizing siderophores in iron‐free grown cultures is also an indication for the high demand of iron by BoFeN1. A positive effect of Fe(III) addition on bacterial growth in general (Dehner et al ., ) and on denitrification (Baalsrud & Baalsrud, ; Pintathong et al ., ) has been demonstrated before. These authors observed increased nitrate utilization when the medium contained concentrations in the μ m range of Fe 3+ .…”

Section: Discussionmentioning

confidence: 78%

Abiotic oxidation of Fe(II) by reactive nitrogen species in cultures of the nitrate‐reducing Fe(II) oxidizer Acidovorax sp. BoFeN1 – questioning the existence of enzymatic Fe(II) oxidation

2012

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Nitrate-reducing, Fe(II)-oxidizing bacteria were suggested to couple with enzymatic Fe(II) oxidation to nitrate reduction. Denitrification proceeds via intermediates (NO2 -, NO) that can oxidize Fe(II) abiotically at neutral and particularly at acidic pH. Here, we present a revised Fe(II) quantification protocol preventing artifacts during acidic Fe extraction and evaluate the contribution of abiotic vs. enzymatic Fe(II) oxidation in cultures of the nitrate-reducing, Fe(II) oxidizer Acidovorax sp. BoFeN1. Sulfamic acid used instead of HCl reacts with nitrite and prevents abiotic Fe(II) oxidation during Fe extraction. Abiotic experiments without sulfamic acid showed that acidification of oxic Fe(II) nitrite samples leads to 5.6-fold more Fe(II) oxidation than in anoxic samples because the formed NO becomes rapidly reoxidized by O(2) , therefore leading to abiotic oxidation and underestimation of Fe(II). With our revised protocol using sulfamic acid, we quantified oxidation of approximately 7 mm of Fe(II) by BoFeN1 within 4 days. Without addition of sulfamic acid, the same oxidation was detected within only 2 days. Additionally, abiotic incubation of Fe(II) with nitrite in the presence of goethite as surface catalyst led to similar abiotic Fe(II) oxidation rates as observed in growing BoFeN1 cultures. BoFeN1 growth was observed on acetate with N(2) O as electron acceptor. When adding Fe(II), no Fe(II) oxidation was observed, suggesting that the absence of reactive N intermediates (NO2 -, NO) precludes Fe(II) oxidation. The addition of ferrihydrite [Fe(OH)(3) ] to acetate/nitrate BoFeN1 cultures led to growth stimulation equivalent to previously described effects on growth by adding Fe(II). This suggests that elevated iron concentrations might provide a nutritional effect rather than energy-yielding Fe(II) oxidation. Our findings therefore suggest that although enzymatic Fe(II) oxidation by denitrifiers cannot be fully ruled out, its contribution to the observed Fe(II) oxidation in microbial cultures is probably lower than previously suggested and has to be questioned in general until the enzymatic machinery-mediating Fe(II) oxidation is identified.

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Section: Discussionmentioning

confidence: 78%

Abiotic oxidation of Fe(II) by reactive nitrogen species in cultures of the nitrate‐reducing Fe(II) oxidizer Acidovorax sp. BoFeN1 – questioning the existence of enzymatic Fe(II) oxidation

2012

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“…The tubes were kept at room temperature for 60 min. Nitrite was assayed in supernatant (harvested from biomass by centrifugation at 4,830 g for 10 min) as described before [2,6].…”

Section: Nitrate Reduction Activity Of Native Cellsmentioning

confidence: 99%

“…Denitrification is typically occurring under anaerobic or anoxic conditions [6,[16][17][18]. In addition, microbially aerobic nitrate reduction has also been reported by soil bacteria such as Pseudomonas, Arthrobacter, Moraxella and Aeromonas [19][20][21].…”

Section: Screening Of Nitrate Reductase Positive-isolatesmentioning

confidence: 99%

“…Recent studies show that metal ions concentration is a critical parameter that affects the ability of denitrifying bacteria to remove nitrate and nitrite [5,6]. Over the past few decades, silver nanoparticles (Ag NPs) have been applied in wide range of commercial product such as catalysts, electronics, printing industry, photographic manufacturing, clothing, food industry, paints, cosmetics products and medical consumptions [7].…”

Section: Introductionmentioning

confidence: 99%

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The Impact of Silver Nanoparticles on Bacterial Aerobic Nitrate Reduction Process

S¹

2014

J Bioprocess Biotech

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Due to the effective antimicrobial properties of silver nanoparticles (Ag NPs), these particles are receiving an extensive interest for applying in wide range of consumer products and water purification systems. Entering the Ag-based material in wastewater system can influence the biological cycle such as nitrogen. Denitrification as a part of nitrogen cycle is an effective biological process in wastewater systems which can be affected by Ag NPs. The objective of this research was to study the impact of Ag NPs on aerobic nitrate reduction. We showed that Rhizobium sp and Azotobacter sp isolates were able to reduce nitrate aerobically. Adding 0.2 ppm of Ag NPs in culture medium of Azotobacter PHB + enhanced the of the nitrate reduction activity about 20% and Ag NPs at this concentration has no significant effect on the nitrate reduction activity of periplasmic extracts of the selected isolates in aerobic conditions. Thus, entering certain ation of Ag NPs in environments has no significant impact on microbial aerobic denitrification as an important part of nitrogen cycle.

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“…As indicated in Figure 20, a high abundance of OTUs belonging to the genus Paracoccus was found in reactors RVC1, PL1, PL2 and PL3 (48, 10, 29 and 27% abundance respectively) and could be regarded as the main responsible for denitrification on the biofilms formed at the electrodes RVC1 and PL2. A few species of this genus are well known to perform denitrification [156][157][158] and they were also previously found in cathodic biofilms performing nitrate reduction [93,154]. A high abundance of OTUs belonging to the genus Paracoccus were also found at the PL1 and PL3 electrodes, although the role of denitrification on those reactors seem to be shared also by other groups of organisms such as Dechloromonas [159] (22 and 31% abundance respectively).…”

Section: Community Structure Assessmentmentioning

confidence: 62%

Microbial electrochemical systems for nitrate removal from diluted streams

Sander¹

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Increased concentrations of nitrogen compounds comprise one important factor contributing to deterioration of aquatic systems, both engineered and natural environments. In engineered Recirculating Aquaculture Systems (RAS), fish excretion and the addition of excess feed lead to build up of ammonium, which is further converted to less toxic nitrate within a (biological) nitrification unit. Although nitrate can accumulate to concentrations higher than 500 mg L -1 NO3 --N, it is suggested that its concentration should not overcome 50 mg L -1 NO3 --N in freshwater cultures and 100 mg L -1 NO3 --N in seawater cultures. Furthermore, the increased environmental regulations and licencing requirements have further imposed considerably stricter limits for discharge of aquaculture effluents to natural environments (i.e. <3 mg L -1 as Total Nitrogen in Queensland prawn farms). Similarly, other industrial activities and commissioned domestic wastewater treatment plants are also required to treat their wastewater streams to very low (diluted) concentrations of nitrogen before discharging them into natural environments. Therefore, either for recirculation of aquaculture water streams or for discharge purposes of various types of wastewaters, it is recommended that the concentration of nitrogen compounds should be monitored and controlled at low levels.Since the organic matter present in wastewaters is generally not sufficient to enable complete biological heterotrophic denitrification, typical denitrification processes require addition of an external carbon source (e.g. methanol). Recently, bioelectrochemical cathodic denitrification have been proposed as an alternative to organic matter addition, providing electrons through an inert conductive surface (cathode) directly to a biofilm performing (autotrophic) denitrification. Furthermore, electrons can be generated abiotically by splitting water, which simultaneously oxygenates the water, providing additional benefits for water reuse in aquaculture systems.Thus, the overall aim of this research project is to develop a Bioelectrochemical system as an alternative technology for denitrification and simultaneous oxygen generation in recirculating streams, which will enable the maintenance of diluted streams with low levels of nitrogen either for recirculation or discharge purposes. Furthermore, the technology should also be applicable as a polishing mechanism for denitrification from other diluted ii streams containing low levels of nitrate, such as secondary (treated) effluents from activated sludge systems.Since Dissimilatory Nitrate Reduction to Ammonium (DNRA) can be considered an undesired competitive pathway during cathodic denitrification, it is important to demonstrate and quantify the occurrence of this pathway. To assess this phenomenon, a carbon cloth cathodic electrode was inoculated with a mix culture denitrifying microbial community and poised at -0.9 V vs. standard hydrogen electrode (SHE). Results showed that more than 40% of nitrogen added as nitrate was co...

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Influence of metal ions and organic carbons on denitrification activity of the halotolerant bacterium, Paracoccus pantotrophus P16 a strain from shrimp pond

Abstract: Waste nitrogen containing compounds, of both organic

Cited by 20 publications

References 49 publications

Abiotic oxidation of Fe(II) by reactive nitrogen species in cultures of the nitrate‐reducing Fe(II) oxidizer Acidovorax sp. BoFeN1 – questioning the existence of enzymatic Fe(II) oxidation

Abiotic oxidation of Fe(II) by reactive nitrogen species in cultures of the nitrate‐reducing Fe(II) oxidizer Acidovorax sp. BoFeN1 – questioning the existence of enzymatic Fe(II) oxidation

The Impact of Silver Nanoparticles on Bacterial Aerobic Nitrate Reduction Process

Microbial electrochemical systems for nitrate removal from diluted streams

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