Enzyme-based method could make CO2 capture economically viable

Codexis (Redwood City, Calif.; www.codexis.com) and CO2 Solution (Quebec City, Canada; www.co2solution.com) have jointly developed a cost-effective method for capturing carbon dioxide from coal-fired power plants. Solvent-based systems for capturing CO2 are relatively well-understood, but they have not been widely deployed because they are energy-intensive and inefficient. Solvent-based approaches involve a trade-off between the kinetics of CO2 absorption by the solvent and the energy required to regenerate the greenhouse gas for sequestration or further use, explains Jim Lalonde, Codexis vice president for biochemistry and engineering R&D. “You want something that binds CO2, but not too tightly,” he says. For example, the solvent monoethanolamine (MEA) offers efficient CO2 capture, but requires high energy to regenerate the gas. The new process depends on two technologies: new forms of the enzyme carbonic anhydrase (CA) that are tolerant of elevated temperatures; and carbon-capture solvents that require less energy to regenerate CO2. Codexis is using a proprietary genetic-screening and directed-evolution approach in developing an early prototype of CA that is stable for 30 min at temperatures of 85°C (natural,…