Modulation of biomass composition by CO2 in two highly productive green microalgae as a sustainable system for byproduct generation Academic Article in Scopus uri icon

abstract

  • Microalgae have the potential to mitigate atmospheric CO2 and generate sustainable byproducts. However, how CO2 impacts C-flux in different species is not clear. This study evaluated the effect of CO2 concentration from industry exhaust gas on growth and biochemical composition of Desmodesmus abundans and Chlorella vulgaris. Gas supply (25 % v/v CO2/air) stimulated growth of both species (1.38 ± 0.02 and 1.56 ± 0.02 g L¿1 for D. abundans and C. vulgaris, respectively). Proteins were the major metabolite at high CO2, especially for C. vulgaris, while D. abundans showed no variation (51 ± 0 and 49 ± 3 % d.w., respectively). Both species exhibited 1.2¿2.2-fold higher carbohydrate and starch content under air. Also, under air, C. vulgaris showed an increase of 2 to 3-fold in lipids, contrary to D. abundans that increased under high CO2 during exponential growth. However, as biomass production was optimal at high CO2, all metabolite concentrations were highest at 25 % CO2. Interestingly, D. abundans exhibited 2 to 3-fold higher pigment content under high CO2, suggesting a differential adaptation to high CO2. Lastly, a rapid and cost-effective protein extraction protocol was optimized (95 °C, 15 min, NaOH 1N) with comparable yields to the standard Micro-Kjeldahl method during exponential growth and some variation at stationary phase (80¿89 % yield). The effect of high CO2 was species-specific, where D. abundans appears as a robust species. Further studies should evaluate the nature of the protein extract for potential applications and consider technical, economic, and environmental feasibility for system scale-up. © 2025 Tecnologico de Monterrey

publication date

  • January 1, 2025