The green microalga Chlamydomonas reinhardtii offers great potential as an innovative green-cell factory by combining fast and inexpensive phototrophic growth with advanced options for genetic engineering. The available cultivation media (e.g. TAP, HSM), however, were developed for lab scale settings and typically result in low cell densities of 2-3⋅107 cells/mL, which are insufficient for many industrial production processes.
Researchers at the Center for Biotechnology (CeBiTec) from Bielefeld University (Germany) have now published a report in Bioresource Technology1 that outlines a new, innovative strategy for fully phototrophic and easy-to-apply high cell density cultivations, to overcome these biomass accumulation limitations. By systematically increasing macro- and micronutrients in combination with elevated light and CO2, the team was able to achieve a 6-fold increase in cell number and biomass accumulation, reaching up to ~2⋅108 cells/mL and 20 g/L biomass dry weight, respectively. This optimized cultivation strategy will support large-scale cultivation efforts of C. reinhardtii and further enable its use in biotechnological applications.