Aims: The objective of this study is to develop kinetic models based on batch experiments describing the growth, CO 2 consumption, and H 2 production of Anabaena variabilis ATCC 29413-U T M as functions of irradiance and CO 2 concentration.
Methods and Results:A parametric experimental study is performed for irradiances from 1120 to 16100 lux and for initial CO 2 mole fractions from 0.03 to 0.20 in argon at pH 7.0 ± 0.4 with nitrate in the medium. Kinetic models are successfully developed based on the Monod model and on a novel scaling analysis employing the CO 2 consumption half-time as the time scale.Conclusions: Monod models predict the growth, CO 2 consumption, and O 2 production within 30%. Moreover, the CO 2 consumption half-time is an appropriate time scale for analyzing all experimental data. In addition, the optimum initial CO 2 mole fraction is 0.05 for maximum growth and CO 2 consumption rates. Finally, the saturation irradiance is determined to be 5,170 lux for CO 2 consumption and growth whereas, the maximum H 2 production rate occurs around 10,000 lux.
Significance and Impact:The study presents kinetic models predicting the growth, CO 2 consumption, and H 2 production of A.variabilis. The experimental and scaling analysis methods can be generalized to other microorganisms.