caa a22 4500 465790364 CHVBK 20180323112022.0 cr unu---uuuuu 170327e19900501xx s 000 0 eng 10.1007/BF02017166 doi (NATIONALLICENCE)springer-10.1007/BF02017166 Ward B. Marine Sciences Program, University of California at Santa Cruz, 95064, Santa Cruz, California, USA aut Kinetics of ammonia oxidation by a marine nitrifying bacterium: Methane as a substrate analogue [Elektronische Daten] [B. Ward] In pure culture, the marine ammonia oxidizer,Nitrosococcus oceanus, exhibits normal Michaelis Menten kinetics with respect to its primary substrate, ammonia.N. oceanus also exhibits a kinetic response to methane. In the absence of methane, oxidation of ammonia is first order with respect to ammonia concentration under atmospheric oxygen concentrations at seawater pH. In the presence of methane, ammonia oxidation is inhibited, and the amount of inhibition is related to the relative concentrations of methane and ammonia. Using semicontinuous batch cultures as a source of organisms for short-term kinetic experiments, I investigated the relationship between ammonia and methane oxidation inN. oceanus by varying the absolute and relative concentration of both substrates. Methane appeared to act as a substrate analogue, and its effect on ammonia oxidation was modeled as a permutation of competitive inhibition involving a cooperative enzyme system. Methane was oxidized byN. oceanus, even in the absence of measurable ammonia oxidation, but the process was inhibited at increasing methane concentrations. Of the two product pools analyzed, an average of 37% of methane oxidized was detected in particulate (cell) material and the remainder was detected in14CO2. The contribution of methane to total carbon assimilation varied with the ratio [CH4]/[NH3] and may be significant under substrate concentrations typical of a dilute aquatic environment. Springer-Verlag New York Inc., 1990 Microbial Ecology Springer-Verlag 19/3(1990-05-01), 211-225 0095-3628 19:3<211 1990 19 248 https://doi.org/10.1007/BF02017166 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF02017166 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Ward B. Marine Sciences Program, University of California at Santa Cruz, 95064, Santa Cruz, California, USA aut NATIONALLICENCE 773 0- Microbial Ecology Springer-Verlag 19/3(1990-05-01), 211-225 0095-3628 19:3<211 1990 19 248 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer