부산대학교 도서관

Emission of greenhouse gases into the atmosphere by human activities leads to global warming. To reduce the level of CO2 the bio-catalytic properties of microbial carbonic anhydrase (CA) can be exploited. The present study aimed to isolate CA producing bacteria from cow saliva. After thorough screening for CA activity in the bacterial cultures, ten isolates were selected. Out of ten bacterial isolates, T5 isolate showed the highest CA activity (83.92 U/mL) and the isolate was identified as Corynebacterium flavescens using 16s rRNA analysis. Various production parameters for the optimum production of CA were optimized. During the optimization, incubation temperature 40°C, agitation speed 120 rpm, and inoculum volume 4%v/v was found to be optimum for CA production. The optimum reaction pH, reaction time and temperature were 7, 10 min and 35°C, respectively. The crude enzyme was tested for the conversion of CO2 into the calcium carbonate (CaCO3) under controlled conditions. The CO2 conversion efficacy of crude CA was observed to be ~45 mg CaCO3/mg protein. The synthesized CaCO3 was analyzed using scanning electron microscopy and X-ray diffraction techniques for particle size, morphology and elemental structure. Calcite precipitation by bacterial CA makes it a potential candidate to be effectively employed in biomimetic CO2 sequestration.