Characterization of a novel recombinant carbonic anhydrase family from the hyperthermophilic archaea Archaeoglobus fulgidus and study of its potential use in atmospheric carbon dioxide capture and utilization

Abstract

Biomimetic CO2 capture emerged as a sustainable and economic technology which could replace existing chemical and physical methods for carbon sequestration. One way of this novel technique is the use of a fast enzyme, carbonic anhydrase, which catalyzes the reversible hydration of carbon dioxide into bicarbonate. Carbonic anhydrases from hyperthermophilic microorganisms gained much interest as a preferable candidate for Carbon Capture Storage and Utilization technologies when compared to those found in mesophilic microorganisms due to their abilities to resist harsh conditions such as elevated temperatures and pH. In this study, a putative carbonic anhydrase protein from the hyperthermophilic archaea Archaeoglobus fulgidus named Af-CA was characterized. Escherichia coli was genetically engineered to produce Af-CA gene cloned into suitable pET expression vectors. Different vectors were used to express the gene as a cytosolic form or a periplasmic version harboring TorA signal peptide sequence. Our results showed that both recombinant protein versions were produced in E. coli cells. The recombinant cytosolic protein was also successfully purified by Nickle affinity chromatography. The purified protein exhibits a large potential for CO2 capture since it catalyzes efficient CO2 hydration activity under different temperatures. In addition, the residual activity was determined after incubating the protein at high temperatures and measuring the residual hydration activity. The protein shows high thermostability and exhibits hyperthermophilic properties. Recombinant E. coli cells expressing both cytoplasmic and periplasmic Af-CA proteins were also efficient in CO2 capture demonstrating that E. coli engineered cells can be used for future applications in carbon sequestration. The novel enzyme CA from Archaeoglobus fulgidus can be an economical biocatalyst used in microbial carbon capture strategies.