Isolation and characterization of carbonic anhydrase enzyme from the Lantana camara plant leaves and its immobilization in polyurethane foam for carbon capture applications

Use of carbonic anhydrase enzyme for capturing CO2 from flue gas is the most promising approach due to its low energy requirement, high selectivity towards CO2, reduced environmental impact, and lower equipment costs. Numerous studies have explored the potential of using carbonic anhydrase from mammalian erythrocytes, yeast, and engineered microorganisms for carbon capture applications. However, there have been relatively few studies focused on CA enzymes obtained from plants, which are an abundant, eco-friendly and inexpensive source material in nature. The CA can be used to enhance the CO2 absorption rate of a conventional amine scrubbing system where absorption takes place at ambient temperature. In this study, the CA enzyme from the plant leaves of Lantana camara was successfully isolated and purified. The purification level of the isolated enzyme was 19-fold. By SDS-PAGE, the molecular weight of the isolated protein was estimated to be 35 kDa. The purified CA was immobilized by the entrapment method in a polyurethane foam. The effects of temperature, pH, and storage stability on the activities of free and immobilized CA were studied. The immobilised enzyme was tested for stability under tertiary amine MDEA (Methyl-diethanolamine) at various concentration levels. In addition, the CO2 sequestration efficiency of both free and immobilized CA enzymes was also evaluated using the CaCO3 deposition method. The results indicate that immobilized CA enzyme from Lantana camara exhibits considerable potential for CO2 capture especially for low-temperature applications. Further research is needed to enhance the thermal and pH stabilities of CA enzymes through protein engineering.