title: Response of poly-phosphate accumulating organisms to free nitrous acid inhibition under anoxic and aerobic conditions.
abstract: The response of free nitrous acid (FNA)-adapted poly-phosphate accumulating organisms (PAOs) to FNA inhibition under aerobic and anoxic conditions was studied. Anoxic P-uptake was 1-6 times more sensitive to the inhibition compared to aerobic P-uptake. The aerobic nitrite reduction rate increased with FNA concentration, accompanied by an equivalent decrease in the oxygen uptake rate, suggesting under high FNA concentration conditions, electrons were channeled to nitrite reduction from oxygen reduction. In contrast, the nitrite reduction rate decreased with increased FNA concentration under anoxic conditions. Anaerobic metabolism of PAO under both anoxic and aerobic conditions was observed at high FNA concentrations. Growth of PAOs decreased sharply with FNA concentration and stopped completely at FNA concentration of 10 μg HNO(2)-N/L. This study, for the first time, investigated the function of nitrite/FNA in an aerobic denitrifying phosphate removal process by evaluating electron as well as energy balances, and provides explanation for FNA inhibition mechanisms.
authors.affiliation: Advanced Environmental Biotechnology Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, SBS-B2N-01, 60 Nanyang Avenue 639798, Singapore. zhouyan@ntu.edu.sg
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhou
authors.forename: Lily
authors.initials: L
authors.lastname: Ganda
authors.forename: Melvin
authors.initials: M
authors.lastname: Lim
authors.forename: Zhiguo
authors.initials: Z
authors.lastname: Yuan
authors.forename: Wun Jern
authors.initials: WJ
authors.lastname: Ng
mesh_terms: D000255:Adenosine Triphosphate / Q000096:biosynthesis; D000332:Aerobiosis / Q000187:drug effects; D000693:Anaerobiosis / Q000187:drug effects; D001419:Bacteria / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D061249:Batch Cell Culture Techniques; D001711:Biotransformation / Q000187:drug effects; D004579:Electron Transport / Q000187:drug effects; D004734:Energy Metabolism / Q000187:drug effects; D005110:Extracellular Space / Q000187:drug effects / Q000378:metabolism; D006003:Glycogen / Q000378:metabolism; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D009608:Nitrous Acid / Q000494:pharmacology*; D010084:Oxidation-Reduction / Q000187:drug effects; D010100:Oxygen / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism; D010758:Phosphorus / Q000378:metabolism; D011122:Polyphosphates / Q000378:metabolism*; D000644:Quaternary Ammonium Compounds / Q000378:metabolism
chemical_list: D009573:Nitrites; D010710:Phosphates; D011122:Polyphosphates; D000644:Quaternary Ammonium Compounds; D010758:Phosphorus; D000255:Adenosine Triphosphate; D006003:Glycogen; D010100:Oxygen; D009608:Nitrous Acid