Enhanced Carbon Sequestration Performance and Mechanism of Adsorption-Catalytic Bifunctional ZIF‑8 Coupled Microalgae

To support the development of a low-carbon economy and contribute to the achievement of carbon neutrality, this study synthesized bifunctional zeolitic imidazolate framework-8-based nanozymes (ZNZs) with dual functionality: CO₂ adsorption and carbonic anhydrase (CA)-mimetic catalytic activity. The influence of ZNZs at varying concentrations on the growth rate of microalgae, chlorophyll and carbohydrate content, and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and CA activity were explored. Results indicated that after the addition of 5 mg/L ZNZs, the growth rate of microalgae increased by 7%. Furthermore, the maximum chlorophyll and carbohydrate contents reached 4.55 and 43.59 mg/L, respectively, which were 12.6 and 4.2% higher than those in the control group. Additionally, Rubisco and CA activity (intra- and extracellular) increased by up to 21.26, 10, and 8.3%, respectively. These findings demonstrate that ZNZs enhance the photosynthetic efficiency of microalgae and increase microalgae's affinity for CO₂, highlighting their promise as a strategy for improving carbon capture and sustainable bioenergy production.