title: Use of real-time QPCR in biokinetics and modeling of two different ammonia-oxidizing bacteria growing simultaneously.
abstract: A real-time quantitative polymerase chain reaction (QPCR) was used to evaluate biokinetic coefficients of Nitrosomonas nitrosa and N. cryotolerans clusters growing simultaneously in a batch mode of ammonia oxidation. The mathematical models based on Monod equation were employed to describe the competitive relationship between these clusters and were fitted to experimental data to obtain biokinetic values. The maximum growth rates (μ(m)), half-saturation coefficients (K(S)), microbial yields (Y) and decay coefficients (k(d)) of N. nitrosa and N. cryotolerans were 1.77 and 1.21 day(-1), 23.25 and 23.06 mg N·L(-1), 16 × 10(8) and 1 × 10(8) copies·mg N(-1), 0.26 and 0.20 day(-1), respectively. The estimated coefficients were applied for modeling continuous operations at various hydraulic retention times (HRTs) with an influent ammonia concentration of 300 mg N·L(-1). Modeling results revealed that ammonia oxidation efficiencies were achieved 55-98 % at 0.8-10 days HRTs and that the system was predicted to be washed out at HRT of 0.7 days. Overall, use of QPCR for estimating biokinetic coefficients of the two AOB cluster growing simultaneously by use of ammonia were successful. This idea may open a new direction towards biokinetics of ammonia oxidation in which respirometry tests are usually employed.
authors.affiliation: School of Environmental Science and Engineering, Pohang University of Science and Technology (POSTECH), San 31, Hyoja-dong, Nam-gu, Pohang, Kyungbuk, 790-784, Republic of Korea.
authors.forename: Kyungjin
authors.initials: K
authors.lastname: Cho
authors.forename: Duong Xuan
authors.initials: DX
authors.lastname: Nguyen
authors.forename: Seungyong
authors.initials: S
authors.lastname: Lee
authors.forename: Seokhwan
authors.initials: S
authors.lastname: Hwang
mesh_terms: D000641:Ammonia / Q000378:metabolism*; D007220:Industrial Waste; D007700:Kinetics; D008954:Models, Biological; D009606:Nitrosomonas / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D010084:Oxidation-Reduction; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D013997:Time Factors; D035501:Uncertainty; D062065:Wastewater / Q000737:chemistry / Q000382:microbiology
chemical_list: D000641:Ammonia; D007220:Industrial Waste; D012336:RNA, Ribosomal, 16S; D062065:Wastewater