Simultaneous carbon dioxide sequestration and utilization for cadaverine production using dual promoters in engineered Escherichia coli strains

Abstract

Human carbonic anhydrase II (hCAII) is a rapid-acting zinc-metalloenzyme that catalyzes CO2 hydration reversibly, with encouraging applications in carbon capture, sequestration, and utilization (CCSU). However, biocatalyst durability is a major challenge. Herein, hCAII is emphasized in 4 different Escherichia coli strains and designated under dual promoters from sigma factor 70 (σ70) and heat shock protein (HSP70A) to suppress the usage of inducer and stimulate activity in heat environments. As a result, hCAII under high-efficient dual promoters regulation retained high residual activity in CO2 biomineralization of 68.8 % after 4 cycles at 40 °C. Moreover, co-expression of CAC9 with lysine decarboxylase (CadA) simultaneously sequestered CO2 release up to 95.7 % and increased cadaverine titer from 18.0 to 36.7 g/L by using E. coli MG1655. The remnant biomass from cadaverine synthesis sustained converting CO2 to 57.9 mg-CaCO3. Thus, the dual promoters design demonstrated the promising potential for CCSU through simultaneous CO2 utilization and cadaverine synthesis.