ABSTRACT
Sulfurihydrogenibium yellowstonense carbonic anhydrase (SyCA) is a well-known thermophilic CA for carbon mineralization. To broaden the applications of SyCA, the activity of SyCA was improved through stepwise engineering and in different cultural conditions, as well as extended to co-expression with other enzymes. The engineered W3110 strains with 4 different T7 RNA polymerase levels were employed for SyCA production. As a result, the best strain WT7L cultured in modified M9 medium with temperature shifted from 37 to 30 °C after induction increased SyCA activity to 9122 U/mL. The SyCA whole-cell biocatalyst was successfully applied for carbon capture and storage (CCS) of CaCO3. Furthermore, SyCA was applied for low-carbon footprint synthesis of 5-aminolevulinic acid (5-ALA) and cadaverine (DAP) by coupling with ALA synthetase (ALAS) and lysine decarboxylase (CadA), suppressing CO2 release to -6.1 g-CO2/g-ALA and -2.53 g-CO2/g-DAP, respectively. Harnessing a highly active SyCA offers a complete strategy for CCSU in a green process.
