The biomass quality of algae used for CO2 sequestration is highly species-specific and may vary over time

T he utilization of microalgae to temporarily sequester CO2 is a hot topic in algal biotechnology. Its association with biomass utilization is often proposed to increase economical revenues. Although C allocation patterns may determine the success or failure of such use of algae, the impact of elevated CO2 on biomass quality has not been investigated systematically. In this study, four algae of different taxonomy and mode of inorganic carbon acquisition were subjected to a transition from low (390 μL L−1) to elevated (1,000 μL L−1) pCO2. Fourier transform infrared spectroscopy, a rapid, nonextractive, and reliable technique, was used to attain the necessary information on all main organic pools concomitantly and with no need for extractive procedures. Cell organic composition was analyzed after 24 hours and 20 days since the transition. T he responses were very species-specific, and the biomass quality was modified over time, indicating that species selection and monitoring of biomass are essential for an adequate control on the quality of the product. Although these concepts may have been in the mind of the illuminated algae users, the experimental evidence is essentially nonexisting. We intended to make a first step towards filling this gap in knowledge.