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Dissolved hydrocarbon metabolism: The concentration‐dependent kinetics of toluene oxidation in some North American estuaries 1
Author(s) -
Button D. K.,
Robertson B. R.
Publication year - 1986
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1986.31.1.0101
Subject(s) - toluene , kinetics , saturation (graph theory) , population , chemistry , hydrocarbon , environmental chemistry , seawater , bacteria , metabolism , artificial seawater , biology , organic chemistry , biochemistry , ecology , physics , demography , mathematics , genetics , quantum mechanics , combinatorics , sociology
The metabolism of toluene by natural populations of marine bacteria, stored to enhance their activity, gave hyperbolic kinetics with saturation at only K t = 0.6 to 3.4 µ g liter −1 . Similarly K t in fresh seawater was 0.26 µ g toluene liter −1 . Freshly collected populations could be moderately active toward toluene, affinity a 2 A = 1.1−37.5 liters g‐cells −1 h −1 . These moderate affinities taken together with the small K t values give an explanation for the failure of most marine bacteria to grow at the expense of a single hydrocarbon. In two experiments there was a significant first‐order region in toluene in the 10–50 µ g liter −1 range. When cultures of Pseudomonas sp. strain T2 were cast in suspended agar blocks to impede diffusion, toluene oxidation still followed hyperbolic kinetics although CO 2 production and organic product formation were characterized by larger Michaelis constants. A large widespread population of bacteria with inducible capacity to metabolize hydrocarbons is indicated. Observed turnover times for toluene were 0.2–40 years with growth rates of 10 −6 h −1 from toluene at 1 µ g liter −1 .