Engineering stable carbonic anhydrases for CO2 capture: a critical review

In the search for green CO2-capture technology to combat global warming, bioengineering of carbonic anhydrases (CAs) is being sought for with target adaptabilities of extreme temperatures and alkaline pH conditions. The modern in silico screening of protein engineering complements the conventional in vitro high-throughput via generation of iteratively cumulating e-library of diverse beneficial mutations. As identified through various studies of randomized and rationalized mutagenesis, different features have been explored to engineer stability in CAs, including improving structural contacts in the protein quaternary architecture with disulfide bonds and salt-bridge networks, as well as enhancing the protein surface electrostatics. Advanced molecular dynamic simulation techniques and progressive training of machine learning-assisted databases are now being used to unravel wild-type CA properties and predict stable variants thereof with greater accuracy than ever before. The best fit CA achieved so forth demonstrates tolerances of up to 107 degrees C at pH >10 with 25-fold enhancement in CO2 mass transfer. This review will provide an overview of different approaches that have been utilized for engineering CAs and will highlight potential challenges and strategies for developing CA-based CO2-capture and sequestration.