Growth CO2 Consumption, and H2 Production of Anabaena Variabilis ATCC 29413-U Under Different Irradiances and CO2 Concentrations

Abstract

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.

Modeling the light attenuation phenomenon during photoautotrophic growth of A. variabilisATCC 29413 in a batch photobioreactor

“…The K iI values obtained by both Haldane and Aiba‐Edward models could be considered as relevant, as they are larger than the saturating light irradiance, which is 460 µE m −2 s −1 . In addition, it is also reported that A. variabilis growth rate was not inhibited by irradiance up to 216 µE m −2 s −1 . Despite the slight differences in the kinetic parameters and SSE values, the Haldane model provides more sensible kinetic parameter values especially the K iI value, which is within the range of light irradiance in the photo‐inhibition phase (460–910 µE m −2 s −1 ) and has the lowest SSE value compared with the other two models thus indicating the most suitable model to represent the experimental data.…”

Flux balancing of light and nutrients in a biofilm photobioreactor for maximizing photosynthetic productivity

“…[40][41][42][43][44]51,52 Moreover, the maximum specific growth rate l max was 4.2 3 10 25 s 21 and the half-saturation and inhibition constants for irradiance, K S;G and K I;G were 38 W/m 2 and 400 W/m 2 , respectively. 54,55 Finally, the relative maximum growth rate and minimum intracellular phosphate mass fraction required for growth, l à max and k q , were 0.24 and 2.7 mg P/g DW. 51 Synechococcus (2 strains) 40 2 9 1 .…”

Bioenergy production using Trichormus variabilis – a review

“…Such data can be used for modeling growth kinetics. In prior work, a kinetic model for growth of T. variabilis was developed based on the Monod model as a function of CO 2 and light intensity . Predictive models are increasingly important as algal biomass generated from wastewater treatment process is being used for the production of biofuels when scaling up from laboratory‐scale to industrial‐scale cultures.…”

“…Temperature is another parameter affecting H 2 photo‐production. A short‐term thermal stress (30–36 °C) enhances nitrogenase activity of T. variabilis The results of studying CO 2 concentration, as a carbon source, demonstrated that an optimum initial CO 2 molar fraction of 0.05 is required for maximum biomass production . Inclusion of a carbon source, such as glucose, also gives rise to further hydrogen production …”