Determination of the specific oxygen uptake rate in microorganisms including electrode time response

The oxygen transfer rate is an important parameter for the aerobic fermentative process. By establishing the real oxygen uptake rate of the target organism we can determine the energetic and process requirements for aeration and agitation. We report in this paper the mathematical and methodological procedure for the determination of the specific oxygen uptake rate (QO(2)), taking the oxygen electrode response into account. This methodology was applied to the QO(2) determination for the Ganoderma lucidum medicinal mushroom while it was being cultured in a stirred reactor in the laboratory. The average value for QO(2) was 0.345 mmol O-2 (g biomass.h)(-1) +/- 0.0171 without taking the electrode time response into account and 0.383 mmol O-2 (g biomass.h)(-1) +/- 0.025 taking the electrode time response into account. Higher response times of the oxygen electrode resulted in a greater differences between the two QO(2) values obtained.