Navigating microalgae under dynamic CO₂ for waste-to-energy conversion

Carbon capture is an important mitigation strategy for the reduction of carbon in the atmosphere. Microalgae can simultaneously capture CO₂ and valorize biomass, turning waste streams into sustainable bioenergy solutions. However, microalgae struggle when CO₂ is either too scarce or too abundant. The scalability of microalgal carbon capture requires the development of strains that can sustain productivity and carbon conversion under fluctuating CO₂ levels. In this review, we reframe CO₂ assimilation in microalgae as a dynamic system shaped by environmental variability. We highlight emerging strategies, including bicarbonate utilization, photobioreactor (PBR) innovation, molecular modeling, and genetic rewiring, that support scalable and specific waste-to-energy conversion. Together, these insights can drive the advancement of microalgal systems tailored for dynamic CO₂ conditions.