Identification of Carbon Dioxide-Producing ...

The present study examined the growth and the CO2 production of indigenous microbial cultures collected from three zones in Chicontepec oil reservoir located in Veracruz, Mexico. Two microbial cultures, coded as NW O and CW O, showed an accelerated growth and higher CO2 production when molasses were used as carbon source. They were selected and identified by molecular-biology techniques as potential candidates to be used in future Microbial Enhanced Oil Recovery studies. To improve CO2 production, a reformulated culture medium was evaluated using only the culture coded as NW O which showed the better growth. Results showed that the reformulated culture medium caused an increase in the production of CO2 from 1.64gL-1to 3.13 gL-1 by the NW O culture. Analysis of 16S rRNA gene libraries allowed the identification of fermentative microorganisms; the NW O culture is composed of Thermoanaerobacter pseudethanolicus and Thermotoga neapolitana; the CW O culture is composed of Caldanaerobacter subterraneus.