Interpretation of the Metabolic Enthalpy Change, ΔHmet, Calculated for Microbial Growth Reactions in Soils
The microcalorimetric method was used to calculate the metabolic enthalpy change per mol of glucose degraded by soil microorganisms, ΔH met. This parameter has been calculated by microcalorimetry for many organic, inorganic and biochemical reactions, but there is only some information about its quantification for microbial growth reactions in soils. Values of ΔH met were calculated for different soil samples collected in Galicia (Spain) and Campinas (Săo Paolo, Brazil). Exponential microbial growth was stimulated in all soil samples by the addition of glucose and power-time curves were recorded. Results showed changes in the values of ΔH met calculated for all the soil samples, suggesting a dependence of this value with the microbial growth rate constant, with the percentage of growth, with the initial number of microorganisms of soil samples, with the quantity of glucose added and with the strain of bacteria growing in soil.
The interpretation of variations of ΔH met provides important qualitative and quantitative information. It reports data that allow to interpret from a qualitative point of view, the increase in biomass as a consequence of the degradation of the organic matter in soil, to understand changes in the percentages of soil organic matter and to know if the microbial population growing in differential soil samples is homogeneous. Therefore, to report that value would be very important in ecological studies, but beforehand, it is necessary to solve some problems that can appear in the experiments done to make the quantification .
Unable to display preview. Download preview PDF.
- 1.H. Yamano and K. Takahashi, Agric. Biol. Chem., 47 (1983) 1493.Google Scholar
- 3.K. Ljungholm, B. Norén and G. Odham, Oikos, 34 (1980) 98.Google Scholar
- 4.U. Mortensen, B. Norén and I. Wadsö, Bull. Ecol. Res. Comm., 17 (1973) 189.Google Scholar
- 7.U. von Stockar and I. Marison, Adv. Biochem. Eng. Biotechnol., 40 (0989) 93.Google Scholar
- 8.M. Murgier and J. P. Belaich, J. Bacteriol., 105 (1971) 573.Google Scholar
- 9.T. Kimura and K. Takahashi, J. Gen. Microbiol., 131 (1985) 3083.Google Scholar
- 10.M. Hashimoto and K. Takahashi, Agric. Biol. Biochem., 46 (1982) 1559.Google Scholar
- 20.D. T. Brook and M. T. Madigan, Biology of Microorganisms, Prentice Hall, New Jersey 1993.Google Scholar
- 21.M. J. Pelczar and E. C. S. Chan, Elements of Microbilogy, McGraw-Hill, 1981.Google Scholar
- 24.L. Gustafsson, Microbes in the sea, Ellis Horwood, Chichester 1987, p. 167.Google Scholar
- 26.M. Alexander, Introduction to Soil Microbiology, Wiley, New York 1961.Google Scholar