Dual-functional potassium argininate for sustainable CO₂ capture and microalgal resource recovery

The CO₂ absorption-microalgae conversion (CAMC) system is a promising technology platform for simultaneous carbon capture and bioproduct generation. This work introduces potassium argininate (ArgK), an amino acid salt with dual functionality, as a novel component to enhance the performance of this CAMC system using Chlorella sp. L166. The ArgK-enhanced process significantly improved system performance, achieving a sevenfold increase in biomass carbon accumulation rate. The final biomass concentration also increased by 396.25% compared with the control. Furthermore, the technology effectively upgraded captured carbon into key biomolecules, boosting protein content by 331.73% to 512.79 mg/L and elevating carbohydrate content to 97.57 mg/L. This performance significantly surpassed that of conventional K₂CO₃-based systems, which resulted in limited protein accumulation. These findings demonstrate the dual role of ArgK as an efficient CO₂ absorbent and biochemical modulator, offering a promising pathway to improve both biomass carbon accumulation efficiency and the economic value of algal biomass. This strategy supports the development of biocompatible, high-performance CAMC system for carbon mitigation and bioresource valorization.