Introduction
Microbial biomass is a fundamental variable in microbiological
research. Expressed as dry weight, the biomass is a
parameter that may be required for the determination of
growth kinetics (Stanbury et al. 1995), yield factors (Ingraham
et al. 1983) or metabolic quotients (Peppler and
Perlman 1979), which are critical for the analysis and
improvement in microbial process efficiencies, as well as
for general physiological research.
A large variety of modern methods for the determination
of biomass in biotechnological processes have been reviewed by Kiviharju et al. (2008), recently. These biomass
estimation techniques are indirect, typically relating physical
(optical density, turbidity, capacitance) or metabolic
(oxygen uptake, CO2 evolution) values to the total biomass
expressed as dry weight. The traditional standard method
for the direct determination of biomass by dry weight measurement
includes drying a sample to constant weight in a
conventional oven. This method generally requires lengthy
drying phases as well as an equilibration step where the
sample temperature is reduced to room temperature in a
desiccator. Accordingly, results are not rapidly available to
allow prompt utilisation of biomass-based information.