Effects of high CO2 concentrations on ecophysiologically different microorganisms

We investigated the effect of increasing CO2 concentrations on the growth and viability of ecophysiologically different microorganisms to obtain information for a leakage scenario of CO2 into shallow aquifers related to the capture and storage of CO2 in deep geological sections. CO2 concentrations in the gas phase varied between atmospheric conditions and 80% CO2 for the aerobic strains Pseudomonas putida F1 and Bacillus subtilis 168 and up to 100% CO2 for the anaerobic strains Thauera aromatica K172 and Desulfovibrio vulgaris Hildenborough. Increased CO2 concentrations caused prolonged lag-phases, and reduced growth rates and cell yields; the extent of this effect was proportional to the CO2 concentration. Additional experiments with increasing CO2 concentrations and increasing pressure (1–5000 kPa) simulated situations occurring in deep CO2 storage sites. Living cell numbers decreased significantly within 24 h at pressures ≥1000 kPa, demonstrating a severe lethal effect for the combination of high pressure and CO2.

► Influence of high CO2 concentration on ecophysiologically different (aerobic, nitrate-reducing, sulphate-reducing) microorganisms.
► Investigation of growth and viability of two aerobic and two anaerobic model organisms.
► CO2 treatment also at elevated pressure up to 5000 kPa.
►  Reduction of growth and viability at high CO2 concentrations.
► Sterilization at high pressure and high CO2 concentrations.