Abstract
Michaelis-Menten kinetic parameters for H2 consumption by three methanogenic habitats were determined from progress curve and initial velocity experiments. The influences of mass transfer resistance, endogenous H2 production, and growth on apparent parameter estimates were also investigated. Kinetic parameters could not be determined for undiluted rumen fluid and some digestor sludge from gas-phase measurements of H2, since mass transfer of H2 across the gas-liquid interface was rate limiting. However, accurate values were obtained once the samples were diluted. H2 consumption by digestor sludge with a long retention time and by hypereutrophic lake sediment was not phase transfer limited. The Km values for H2 uptake by these habitats were similar, with means of 5.8, 6.0, and 7.1 μM for rumen fluid, digestor sludge, and sediment, respectively. Vmax estimates suggested a ratio of activity of approximately 100 (rumen fluid):10 (sludge):1 (sediment); their ranges were as follows: rumen fluid, 14 to 28 mM h−1; Holt sludge, 0.7 to 4.3 mM h−1; and Wintergreen sediment, 0.13 to 0.49 mM h−1. The principles of phase transfer limitation, studied here for H2, are the same for all gaseous substrates and products. The limitations and errors associated with gas phase determination of kinetic parameters were evaluated with a mathematical model that combined mass transport and Michaelis-Menten kinetics. Three criteria are described which can be used to evaluate the possibility that a phase transfer limitation exists. If it does not exist, (i) substrate consumption curves are Michaelis-Menten and not first order, (ii) the Km is independent of initial substrate concentration, and (iii) the Km is independent of biomass (Vmax) and remains constant with dilution of sample. Errors in the Michaelis-Menten kinetic parameters are caused by endogenously produced H2, but they were <15% for rumen fluid and 10% for lake sediment and digestor sludge. Increases in Vmax during the course of progress curve experiments were not great enough to produce systematic deviations from Michaelis-Menten kinetics.
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Selected References
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- Abram J. W., Nedwell D. B. Hydrogen as a substrate for methanogenesis and sulphate reduction in anaerobic saltmarsh sediment. Arch Microbiol. 1978 Apr 27;117(1):93–97. doi: 10.1007/BF00689357. [DOI] [PubMed] [Google Scholar]
- Abram J. W., Nedwell D. B. Inhibition of methanogenesis by sulphate reducing bacteria competing for transferred hydrogen. Arch Microbiol. 1978 Apr 27;117(1):89–92. doi: 10.1007/BF00689356. [DOI] [PubMed] [Google Scholar]
- Czerkawski J. W., Harfoot C. G., Breckenridge G. The relationship between methane production and concentrations of hydrogen in the aqueous and gaseous phases during rumen fermentation in vitro. J Appl Bacteriol. 1972 Dec;35(4):537–551. doi: 10.1111/j.1365-2672.1972.tb03735.x. [DOI] [PubMed] [Google Scholar]
- Duggleby R. G., Morrison J. F. The analysis of progress curves for enzyme-catalysed reactions by non-linear regression. Biochim Biophys Acta. 1977 Apr 12;481(2):297–312. doi: 10.1016/0005-2744(77)90264-9. [DOI] [PubMed] [Google Scholar]
- Eisenthal R., Cornish-Bowden A. The direct linear plot. A new graphical procedure for estimating enzyme kinetic parameters. Biochem J. 1974 Jun;139(3):715–720. doi: 10.1042/bj1390715. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hungate R. E. Hydrogen as an intermediate in the rumen fermentation. Arch Mikrobiol. 1967;59(1):158–164. doi: 10.1007/BF00406327. [DOI] [PubMed] [Google Scholar]
- Hungate R. E., Smith W., Bauchop T., Yu I., Rabinowitz J. C. Formate as an intermediate in the bovine rumen fermentation. J Bacteriol. 1970 May;102(2):389–397. doi: 10.1128/jb.102.2.389-397.1970. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kaspar H. F., Wuhrmann K. Kinetic parameters and relative turnovers of some important catabolic reactions in digesting sludge. Appl Environ Microbiol. 1978 Jul;36(1):1–7. doi: 10.1128/aem.36.1.1-7.1978. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lovley D. R., Dwyer D. F., Klug M. J. Kinetic analysis of competition between sulfate reducers and methanogens for hydrogen in sediments. Appl Environ Microbiol. 1982 Jun;43(6):1373–1379. doi: 10.1128/aem.43.6.1373-1379.1982. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lovley D. R., Klug M. J. Intermediary metabolism of organic matter in the sediments of a eutrophic lake. Appl Environ Microbiol. 1982 Mar;43(3):552–560. doi: 10.1128/aem.43.3.552-560.1982. [DOI] [PMC free article] [PubMed] [Google Scholar]
- McDougall E. I. Studies on ruminant saliva. 1. The composition and output of sheep's saliva. Biochem J. 1948;43(1):99–109. [PMC free article] [PubMed] [Google Scholar]
- Mountfort D. O., Asher R. A., Mays E. L., Tiedje J. M. Carbon and electron flow in mud and sandflat intertidal sediments at delaware inlet, nelson, new zealand. Appl Environ Microbiol. 1980 Apr;39(4):686–694. doi: 10.1128/aem.39.4.686-694.1980. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ngian K. F., Lin S. H., Martin W. R. Effect of mass transfer resistance on the Lineweaver-Burk plots for flocculating microorganisms. Biotechnol Bioeng. 1977 Dec;19(12):1773–1784. doi: 10.1002/bit.260191204. [DOI] [PubMed] [Google Scholar]
- Robinson J. A., Strayer R. F., Tiedje J. M. Method for measuring dissolved hydrogen in anaerobic ecosystems: application to the rumen. Appl Environ Microbiol. 1981 Feb;41(2):545–548. doi: 10.1128/aem.41.2.545-548.1981. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Smith P. H., Mah R. A. Kinetics of acetate metabolism during sludge digestion. Appl Microbiol. 1966 May;14(3):368–371. doi: 10.1128/am.14.3.368-371.1966. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Strayer R. F., Tiedje J. M. Kinetic parameters of the conversion of methane precursors to methane in a hypereutrophic lake sediment. Appl Environ Microbiol. 1978 Aug;36(2):330–340. doi: 10.1128/aem.36.2.330-340.1978. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Winfrey M. R., Nelson D. R., Klevickis S. C., Zeikus J. G. Association of hydrogen metabolism with methanogenesis in Lake Mendota sediments. Appl Environ Microbiol. 1977 Feb;33(2):312–318. doi: 10.1128/aem.33.2.312-318.1977. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Wolin M. J. Metabolic interactions among intestinal microorganisms. Am J Clin Nutr. 1974 Nov;27(11):1320–1328. doi: 10.1093/ajcn/27.11.1320. [DOI] [PubMed] [Google Scholar]
