Flow Microcalorimetric Studies of Yeast Growth: Fundamental Aspects

Abstract

The importance of factors such as cultural conditions e.g. organism background, inoculum density and glucose concentration are explored and their effects on the experimental recording discussed. The relevance of these findings to microbial microcalorimetry in general and to microcalorimetric identification of organisms in particular is described. The conclusions drawn are (i) that microbial identification by microcalorimetry is not possible and (ii) that great caution must be exercised in interpreting metabolic data derived from microcalorimetric studies.

Characterization of commercial yeast strains by flow microcalorimetry

“…To standardize the inoculum used in each test, inocula were stored at -196°C. The method of preparation, unless indicated otherwise, was as described previously (Perry et al 1979) and utilized the 1 litre growth regimen.…”

“…The flow microcalorimeter (LKB type 10700-l), its operation and the establishment of the calorimetric incubation have been described previously (Perry et al 1979). Grade A maltose monohydrate containing 0.17% (w/w) glucose, used throughout this study, was obtained from Calbiochem, La Jolla, California, USA.…”

“…Microcalorimetry, particularly flow microcalorimetry, has been applied, with considerable success, to many areas of microbiology (Beezer 1980). The reco:d of heat production as a function of time during microbial growth and metabolism, a power-time curve (p-t curve; Belaich et al 1981), can be characteristic of a micro-organism when recorded under strictly controlled cultural conditions (Perry et at. 1979) and may be used to characterize a large number of closely related strains (Russell et al 1975;Fujita et al 1978;.…”

Application of flow cytometry to rapid microbial analysis in food and drinks industries

“…Indirect methods are based either on the measurement of the products of cell metabolism or on the quantification of change of chemical properties of the culture medium induced by microorganisms growth. ATP assay [19], radioimmunoassay (RIA) [7], enzyme-linked immuno-* Correspondence and reprints absorbent assay (ELISA) [23], microcalorimetry [11], electrical impedance [5] and radiometry [20] belong to this group.…”

Calorimetric study of the endogenous metabolism of yeast.

“…Regarding yeast, the thermal properties of metabolism and growth have been reported by several authors (1)(2)(3)(4)(5)(6)(7)(8). Previously, the present authors made thermal studies on yeast growth using a twin-type rotatory calorimeter specially designed for microbiological uses (9).…”