In this study, Magnetic Cellulose Crystals (MCCs) are modified, characterized and used to immobilization of Bovine Carbonic Anhydrase (BCA). BCA enzyme was covalently attached via glutaraldehyde to two MCCs materials: a magnetic cellulose I polymorph (MCC-I) and a mixture of magnetic cellulose I and II polymorphs (MCC-I-II). The esterase activity of BCA immobilized into MCC-I (BCA-MCC-I) and MCC-I-II (BCA-MCC-I-II) was 228 and 318 % greater than the free enzyme, respectively. At 60 °C, BCA-MCC-I-II maintained up to 80 % of its initial activity, after 48 h. The activity of BCA-MCC-I was higher in comparison with the other derivatives at acid pH, conserved the 80 % of initial activity after 48 h. The high activity and stability of achieved biocatalysts are considering a great starting step to develop green strategies for CO2 mitigation, using eco-friendly materials, like cellulose. These findings are expected to impact enzyme-based CO2 transformation strategies and contribute to mitigate global warming.