AISLAMIENTO Y CARACTERIZACIÓN DE CEPAS BACTERIANAS AEROBIAS AUTOCTÓNAS DE YACIMIENTOS PETROLEROS PRODUCTORAS DE BIOSURFACTANTES PARA SU APLICACIÓN EN TÉCNICAS DE MEOR

Abstract

In this study, the isolation and identification of a biosurfactante producer microbial consortium from the oil reservoir of a Mexican oil field (Chicontepec) is described. These isolates were able to grow up at 30, 40 and 60 °C with three different carbon sources (glycerol, kerosene and molasses). One of the isolates grew at 40°C with the maximum production of biosurfactant. These isolates exhibed biochemical, morphological and physiological characteristics of the Pseudomonas aeruginosa. Moreover, the partial sequencing of the 16S ribosomal deoxyribonucleic acid gene of the selected isolates assigned them to the above mentioned group. The biosurfactant produced by these isolates significantly reduced surface tension of the culture media, from 60 to 40 mN/m with a Critical Micelle Concentration of 1112.5 mg/L. The purified biosurfactant production yield was 26 mg of ramnolipids/L. The biosurfactant was exposed to different temperatures from 50 to 121°C during 1 h, and was found to be thermostable. The infrared spectroscopy technique revealed that the partial structural characterization of the biosurfactant mixture of the compounds was composed of polysaccharides in nature. Finally, bacterial strains evaluated in this work can be applied in methods of microbial enhanced oil recovery at mature oil wells.