Gas balance method for testing of microbial growth efficiency after carbon substrate pulse

The present paper deals with the analysis of the amount of oxygen utilized for oxidation of a small dose of carbon substrate in carbon limited Brevibacterium flavum culture. The ratio of the measured oxygen consumption (mo2) to the amount of added carbon substrate (ms) gives a stoichiometric coefficient of the biological oxidation equation. A linear relationship between mo2 and ms was observed. To compare the efficiency of different carbon substrate utilization there has been introduced a normalized value β = m/m. There exists a simple relationship between β and the thermodynamical growth efficiency η The theoretical considerations are proved by experimental results with β, η and Yx/s in a chemostat culture at various medium flow rates.