Improving the heterotrophic media of three Chlorella vulgaris mutants toward optimal color, biomass and protein productivity

Abstract

The high production costs and unappealing sensory properties still limit the widespread commercialization of microalgae feedstocks. Therefore, this work focused on fine-tuning the heterotrophic medium composition to cultivate novel green, yellow, and white Chlorella vulgaris mutant strains. Screening assays were carried out to select the most significant factors, and different nutrient concentrations were optimized by modelling biomass and protein productivity, specific growth rate, and color, via response surface methodology. The biomass and protein productivities achieved by these strains were improved by up to 70% and 94%, respectively. Additionally, biomass color was correlated with medium composition for the first time, allowing the improvement of the yellow and white mutant colorations by 20%. Overall, the findings of this study are vital to overcoming the challenges of the biobased industry, allowing the enhancement of the cost-effectiveness, attractiveness, and nutritional profiles of microalgae-based products in different markets and applications.