title: Bioaugmentation of a wastewater bioreactor system with the nitrous oxide-reducing denitrifier Pseudomonas stutzeri strain TR2.
abstract: In bioaugmentation technology, survival of inoculant in the treatment system is prerequisite but remains to be a crucial hurdle. In this study, we bioaugmented the denitrification tank of a piggery wastewater treatment system with the denitrifying bacterium Pseudomonas stutzeri strain TR2 in two pilot-scale experiments, with the aim of reducing nitrous oxide (N(2)O), a gas of environmental concern. In the laboratory, strain TR2 grew well and survived with high concentrations of nitrite (5-10 mM) at a wide range of temperatures (28-40°C). In the first augmentation of the pilot-scale experiment, strain TR2 inoculated into the denitrification tank with conditions (30°C, ~0.1 mM nitrite) survived only 2-5 days. In contrast, in the second augmentation with conditions determined to be favorable for the growth of the bacterium in the laboratory (40-45°C, 2-5 mM nitrite), strain TR2 survived longer than 32 days. During the time when the presence of strain TR2 was confirmed by quantitative real-time PCR, N(2)O emission was maintained at a low level even under nitrite-accumulating conditions in the denitrification and nitrification tanks, which provided indirect evidence that strain TR2 can reduce N(2)O in the pilot-scale system. Our results documented the effective application of growth conditions favorable for strain TR2 determined in the laboratory to maintain growth and performance of this strain in the pilot-scale reactor system and the decrease of N(2)O emission as the consequence.
authors.affiliation: Tohoku Gakuin University, 1-13-1 Chuo, Tagajo, Miyagi 985-8537, Japan.
authors.forename: Wakako
authors.initials: W
authors.lastname: Ikeda-Ohtsubo
authors.forename: Morio
authors.initials: M
authors.lastname: Miyahara
authors.forename: Sang-Wan
authors.initials: SW
authors.lastname: Kim
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yamada
authors.forename: Masaki
authors.initials: M
authors.lastname: Matsuoka
authors.forename: Akira
authors.initials: A
authors.lastname: Watanabe
authors.forename: Shinya
authors.initials: S
authors.lastname: Fushinobu
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Wakagi
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Shoun
authors.forename: Keisuke
authors.initials: K
authors.lastname: Miyauchi
authors.forename: Ginro
authors.initials: G
authors.lastname: Endo
mesh_terms: D000693:Anaerobiosis; D000818:Animals; D019149:Bioreactors; D058440:Denitrification; D008372:Manure; D058465:Nitrification; D009573:Nitrites / Q000378:metabolism; D009609:Nitrous Oxide / Q000378:metabolism*; D010865:Pilot Projects; D044223:Pseudomonas stutzeri / Q000254:growth & development / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D034421:Sus scrofa; D013696:Temperature; D062065:Wastewater / Q000737:chemistry*
chemical_list: D008372:Manure; D009573:Nitrites; D009609:Nitrous Oxide; D062065:Wastewater