Inhibition or promotion of biodegradation of nitrate by Paracoccus sp. in the presence of nanoscale zero-valent iron.

To investigate the effect of nanoscale zero-valent iron (nZVI) on the growth of Paracoccus sp. strain and biodenitrification under aerobic conditions, specific factors were studied, pH, concentration of nitrate, Fe (II) and carbon dioxide. Low concentration of nZVI (50mg/L) promoted both cell growth and biodegradation of nitrate which rose from 69.91% to 76.16%, while nitrate removal fell to 67.10% in the presence of high nZVI concentration (1000 mg/L). This may be attributed to the ions produced in nZVI corrosion being used as an electron source for the biodegradation of nitrate. However, the excess uptake of Fe (II) causes oxidative damage to the cells. To confirm this, nitrate was completely removed after 20 h when 100mg/L Fe (II) was added to the solution, which is much faster than the control (86.05%, without adding Fe (II)). However, nitrate removal reached only 45.64% after 20 h, with low cell density (OD 600=0.62) in the presence of 300 mg/L Fe (II). Characterization techniques indicated that nZVI adhered to microorganism cell membranes. These findings confirmed that nZVI could affect the activity of the strain and consequently change the biodenitrification.

[1]  Am Jang,et al.  Reduction of highly concentrated nitrate using nanoscale zero-valent iron: Effects of aggregation and catalyst on reactivity , 2011 .

[2]  Kara L Nelson,et al.  Bactericidal effect of zero-valent iron nanoparticles on Escherichia coli. , 2008, Environmental science & technology.

[3]  S. Pavlou,et al.  A kinetic study of hydrogenotrophic denitrification , 2006 .

[4]  R. Naidu,et al.  Removal of nitrate using Paracoccus sp. YF1 immobilized on bamboo carbon. , 2012, Journal of hazardous materials.

[5]  M. Rivett,et al.  Nitrate attenuation in groundwater: a review of biogeochemical controlling processes. , 2008, Water research.

[6]  Y. An,et al.  Decreasing ammonium generation using hydrogenotrophic bacteria in the process of nitrate reduction by nanoscale zero-valent iron. , 2009, The Science of the total environment.

[7]  G. Mitchell,et al.  Assessing the impact of nano- and micro-scale zerovalent iron particles on soil microbial activities: particle reactivity interferes with assay conditions and interpretation of genuine microbial effects. , 2011, Chemosphere.

[8]  Pedro J J Alvarez,et al.  Effects of nano-scale zero-valent iron particles on a mixed culture dechlorinating trichloroethylene. , 2010, Bioresource technology.

[9]  Pei-Jen Chen,et al.  Toxicity assessments of nanoscale zerovalent iron and its oxidation products in medaka (Oryzias latipes) fish. , 2011, Marine pollution bulletin.

[10]  Effect of bimetallic and polymer-coated Fe nanoparticles on biological denitrification. , 2010, Bioresource technology.

[11]  Xin Zhang,et al.  2,4,6-Trinitrotoluene reduction kinetics in aqueous solution using nanoscale zero-valent iron. , 2009, Journal of hazardous materials.

[12]  S. Pavlou,et al.  Hydrogenotrophic denitrification of potable water: a review. , 2010, Journal of hazardous materials.

[13]  Lu Lv,et al.  Nitrate reduction using nanosized zero-valent iron supported by polystyrene resins: role of surface functional groups. , 2011, Water research.

[14]  R. Naidu,et al.  Kaolinite-supported nanoscale zero-valent iron for removal of Pb2+ from aqueous solution: reactivity, characterization and mechanism. , 2011, Water research.

[15]  Li-na Shi,et al.  Removal of chromium (VI) from wastewater using bentonite-supported nanoscale zero-valent iron. , 2011, Water research.

[16]  R. Naidu,et al.  Impact of iron-based nanoparticles on microbial denitrification by Paracoccus sp. strain YF1. , 2013, Aquatic toxicology.

[17]  J. Trevors,et al.  Effect of pH and Temperature on Denitrification Gene Expression and Activity in Pseudomonas mandelii , 2009, Applied and Environmental Microbiology.

[18]  Hao Li,et al.  Antibacterial activities of zinc oxide nanoparticles against Escherichia coli O157:H7 , 2009, Journal of applied microbiology.

[19]  X. Qiu,et al.  Debromination of polybrominated diphenyl ethers by Ni/Fe bimetallic nanoparticles: influencing factors, kinetics, and mechanism. , 2011, Journal of hazardous materials.

[20]  Gordon C. C. Yang,et al.  Chemical reduction of nitrate by nanosized iron: kinetics and pathways. , 2005, Water research.

[21]  R. Naidu,et al.  Dechlorination of p-chlorophenol from aqueous solution using bentonite supported Fe/Pd nanoparticles: Synthesis, characterization and kinetics , 2011 .

[22]  K. Shin,et al.  Microbial reduction of nitrate in the presence of nanoscale zero-valent iron. , 2008, Chemosphere.

[23]  A. E. Greenberg,et al.  Standard methods for the examination of water and wastewater : supplement to the sixteenth edition , 1988 .

[24]  M. Yao,et al.  Use of zero-valent iron nanoparticles in inactivating microbes. , 2009, Water research.

[25]  E. W. V. van Niel,et al.  Simultaneous Nitrification and Denitrification in Aerobic Chemostat Cultures of Thiosphaera pantotropha , 1988, Applied and environmental microbiology.

[26]  Hang-sik Shin,et al.  Mechanism study of nitrate reduction by nano zero valent iron. , 2011, Journal of hazardous materials.

[27]  Chen Lin,et al.  Biodegradation of naphthalene by strain Bacillus fusiformis (BFN). , 2010, Journal of hazardous materials.

[28]  Donald Lucas,et al.  Oxidative stress induced by zero-valent iron nanoparticles and Fe(II) in human bronchial epithelial cells. , 2009, Environmental science & technology.

[29]  Armand Masion,et al.  Relation between the redox state of iron-based nanoparticles and their cytotoxicity toward Escherichia coli. , 2008, Environmental science & technology.

[30]  R. Naidu,et al.  Influence of zero-valent iron nanoparticles on nitrate removal by Paracoccus sp. , 2014, Chemosphere.

[31]  N. Cicek,et al.  Kinetics of hydrogen-dependent denitrification under varying pH and temperature conditions. , 2005, Biotechnology and bioengineering.

[32]  J. Prosser,et al.  The impact of zero-valent iron nanoparticles on a river water bacterial community. , 2010, Journal of hazardous materials.

[33]  Y. Yoo,et al.  Biological nitrate removal in industrial wastewater treatment: which electron donor we can choose , 2009, Applied Microbiology and Biotechnology.

[34]  M. Wiesner,et al.  Chemical stability of metallic nanoparticles: a parameter controlling their potential cellular toxicity in vitro. , 2009, Environmental pollution.