The potential mechanism of carbon-light match regulated microalga metabolism: Insights from a multi-omics analysis

Microalgae represent a promising nature-based solution for simultaneous carbon mitigation and renewable bioresource production. Carbon availability and light intensity are fundamental drivers of microalgal metabolism, yet the interactive mechanisms remain inadequately characterized. This study integrated physiological, multi-omics, and biochemical analysis to investigate the responses of Dunaliella to varying carbon-light synergies. The optimal carbon-light match significantly promoted microalgal growth and carbon fixation capacity, achieving increases of 36.0 % and 47.5 % over the control, respectively. This was supported by the upregulated genes related to photosynthesis, along with the enhanced porphyrin metabolism and promoted DNA replication. Stimulated by enhanced photosynthetic electron transport, the intracellular pools of ATP and NADPH expanded significantly, exhibiting 4.35- and 6.02-fold increases relative to the control, respectively. The multi-omics analysis further demonstrated that optimal synergy remodeled intracellular energy metabolism and carbon flux distribution. Microalgal cells achieved a dynamic balance between ATP generation and elevated metabolic demands to drive cell proliferation. The enhanced photosynthetic carbon flux was predominately channeled to the pyruvate node, accelerating the Acetyl-CoA biosynthesis. Moreover, the promoted carbon skeleton was subsequently partitioned to TCA cycle, amino metabolism, and lipid synthesis. This study provided a theoretical basis for how carbon-light match orchestrated microalgal metabolism, offering insights for optimizing microalgal-based technology.