Biofixation of CO2 on a pilot scale: Scaling of the process for industrial application

Abstract

The use of Spirulina in CO2 biofixation, aside from its contribution to reducing the greenhouse effect, enables the use of the biomass to obtain biocompounds. In this work, Spirulina platensis was used for CO2 biofixation under different conditions of inorganic carbon. S. platensis was inoculated into 200 L bioreactors containing modified Zarrouk’s medium (concentration of the carbon was from 1.0 to 2.0 g.L-1). CO2 (12% v/v) was injected into the culture medium intermittently to maintain the inorganic carbon concentration and pH levels favorable for growth. The values of the maximum specific growth rate obtained for both conditions were the same (0.76 day-1). However, the culture in which a concentration of 2.0 g.L-1 of NaHCO3 was maintained allowed higher concentrations of biomass (1.0 g.L-1) and higher productivity (0.11 g.L-1.d-1) to be obtained as compared to the same parameters obtained in cultures containing 1.0 g.L-1 of NaHCO3. Key words: Bioreactor, cyanobacteria, microalgae, Spirulina.