Biochemical trade-offs and opportunities of commercialized microalgae cultivation under increasing carbon dioxide

Microalgae's exceptional photosynthetic prowess, CO₂ adaptation, and high-value bioproduct accumulation make them prime candidates for microorganism-based biorefineries. However, most microalgae research emphasizes downstream processes and applications rather than fundamental biomass and biochemical balances and kinetic under the influence of greenhouse gases such as CO₂. Therefore, three distinctly different microalgae species were cultivated under 0% to 20% CO₂ treatments to examine their biochemical responses, biomass production and metabolite accumulations. Using a machine learning approach, it was found that Chlorella sorokiniana showed a positive relationship between biomass and chl a, chl b, carotenoids, and carbohydrates under increasing CO₂ treatments, while Chlamydomonas angulosa too displayed positive relationships between biomass and all studied biochemical contents, with minimal trade-offs. Meanwhile, Nostoc sp. exhibited a negative correlation between biomass and lipid contents under increasing CO₂ treatment. The study showed the potential of Chlorella, Chlamydomonas and Nostoc for commercialization in biorefineries and carbon capture systems where their trade-offs were identified for different CO₂ treatments and could be prioritized based on commercial objectives. This study highlighted the importance of understanding trade-offs between biomass production and biochemical yields for informed decision-making in microalgae cultivation, in the direction of mass carbon capture for climate change mitigation.