Potential of carbonic anhydrase and urease bacteria for sequestration of CO2 into aerated concrete

The present study aimed to investigate the potential of bacterial strains from cement kiln dust (CKD) to sequestrate atmospheric CO2 into aerated concrete as a functional for carbonic anhydrase (CA) and urease enzymes. Five samples of CKD was collected from Cement Industries of Malaysia Berhad (CIMA). The most potent bacterial isolates were selected and adapted to grow in 5% of CO2 and in bio-aerated concrete medium. CA enzyme was detected by using a solution of 1.8 g of p-NPA (p-nitrophenyl acetate) and 25 mg of ampicillin at 7-pH. The results of thioglycolate broth medium assay indicated that the bacterial isolates were facultative anaerobic. Furthermore, the results of candle jar test reflected that the bacterial isolates have the ability to survive with 5% of CO2 concentrations. Two bacterial isolates distinctly grow in bio-aerated concrete simulation medium, while only one bacterial isolate was the most potent and has produced in a powder form using freeze dryer to be ready to apply in bio-aerated concrete.