The carbon fixation is one of the most important worldwide issues for global sustainability and for prevention of global warming. Development of ways to reduce the atmospheric CO2 concentration is urgent demand. Biocatalysts such as carbonic anhydrase and formate dehydrogenase (FDH) could be utilized for carbon capture and sequestration. Though carbonic anhydrase catalyzes the rapid hydration of CO2, formate dehydrogenase could directly convert CO2 into formate through reduction reaction. Most of the NAD-independent FDHs used for CO2 reduction are oxygen-labile due to their tungsten or molybdenum-containing active site. For practical application under aerobic condition, NAD-dependent FDHs, which are widely used for enzymatic NADH regeneration, are currently applied to CO2 reduction with advantages of oxygen stability and easy recombinant expression. However, NAD-dependent FDH from Candida boidinii (CbFDH), which is commercially available and is the most widely used, has very low CO2 reduction activity. Five NAD-dependent FDHs reported to have more acidic optimum pH than that of CbFDH were examined. Among tested enzymes, formate dehydrogenase from Thiobacillus sp. FDH (TsFDH) showed the highest CO2 reduction activity under acidic condition. The ordered ternary complex model for two substrates enzyme kinetics showed TsFDH had 33.7-fold higher catalytic efficiency (kcat/Km) than that of CbFDH in the reduction of CO2. Formate produced through the CO2 reduction reaction was detected. Further discussion will be presented.

Efficient CO<sub>2</sub> reduction by acidophilic NAD-dependent formate dehydrogenases

245th National Meeting (2013)

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Efficient CO2 reduction by acidophilic NAD-dependent formate dehydrogenases

Efficient CO₂ reduction by acidophilic NAD-dependent formate dehydrogenases