Engineered yeast for enhanced CO2 mineralization

Abstract

In this work, a biologically catalysed CO₂ mineralization process for the capture of CO₂ from point sources was designed, constructed at a laboratory scale, and, using standard chemical process scale-up protocols, was modelled and evaluated at an industrial scale. A yeast display system in Saccharomyces cerevisae was used to screen several carbonic anhydrase isoforms and mineralization peptides for their impact on CO₂ hydration, CaCO₃ mineralization, and particle settling rate. Enhanced rates for each of these steps in the CaCO₃ mineralization process were confirmed using quantitative techniques in lab-scale measurements. The effect of these enhanced rates on the CO₂ capture cost in an industrial scale CO₂ mineralization process using coal fly ash as the CaO source was evaluated. The model predicts a process using bCA2-yeast and fly ash is ∼10% more cost effective per tonne of CO₂ captured than a process with no biological molecules, a savings not realized by wild-type yeast and high-temperature stable recombinant CA2 alone or in combination. The levelized cost of electricity for a power plant using this process was calculated and scenarios in which this process compares favourably to CO₂ capture by MEA absorption process are presented.