Mitigation carbon emissions by microalgae: Assessing the viability of culture Arthrospira platensis grown on high CO₂ concentrations

¹ Lomonosov Moscow State University, Moscow, Russia
² Joint Institute for High Temperatures of Russian Academy of Science, Moscow, Russia

^* Corresponding author: chernova_nadegda@mail.ru

Abstract

In this work, experimentally evaluated the viability of a consortium microalgae Arthrospira platensis rsemsu P Bios with heterotrophic bacteria when cultivated in a gas-air mixture with high concentrations of CO2 (from 0.04 to 9%). A laboratory setup was created to test the viability of microalgae strains at high concentrations of CO2. The experiments were carried out using 12 photobioreactors with a culture medium volume of 4 L each, placed in a gas chamber, which makes it possible to create elevated CO2 concentrations in the gas-air medium. The maximum growth rate of biomass of microalgae A. platensis is 170 mg/(l per day), the maximum absolute increase in biomass for 12 days is 1540 mg/l. The relatively low growth rate and absolute increase in the biomass of A. platensis at all concentrations of CO2 in the gas-air mixture may indicate that this culture requires a longer laboratory adaptation to high concentrations of CO2. The high cell viability found in all experiments by cytochemical staining of cells with methylene blue indicates the acquired tolerance of the culture to elevated CO2 concentrations (3–9%). However, after 12 days of the experiment with 9% CO2, morphometric signs of cell suppression are detected, which is expressed in deviations of the cell shape from normal, elongation (lack of division) and an increase in the number of dead cells. Quantitative characteristics of the microalgae consortium viability have been obtained.