Conversion of carbon dioxide to oxaloacetate using integrated carbonic anhydrase and phosphoenolpyruvate carboxylase

The development and implementation of strategies for CO₂ mitigation are necessary to counteract the greenhouse gas effect of carbon dioxide emissions. To demonstrate the possibility of simultaneously capturing CO₂ and utilizing four-carbon compounds, an integrated system using CA and PEPCase was developed, which mimics an in vivo carbon dioxide concentration mechanism. We first cloned the PEPCase 1 gene of the marine diatom Phaeodactylum tricornutum and produced a recombinant PtPEPCase 1. The affinity column purified PtPEPCase 1 exhibited specific enzymatic activity (5.89 U/mg). When the simultaneous and coordinated reactions of CA from Dunaliella sp. and the PtPEPCase 1 occurred, more OAA was produced than when only PEPCase was present. Therefore, this integrated CA-PEPCase system can be used not only to capture CO₂ but also for a new technology to produce value-added four-carbon platform chemicals.