CAMBIOS EN LOS BIOMARCADORES DE LA FRACCIÓN DE HIDROCARBUROS SATURADOS EN UN ENSAYO DE BIORREMEDIACIÓN CON UN CRUDO EXTRAPESADO

Biomarkers in the saturated hydrocarbon fraction ( n -alkanes, pristane, phytane, terpanes, and steranes) were evaluated in a 90-day bioremediation assay with extra heavy crude (10o API). Based on the presence of an unresolved complex mixture (UCM), deficiency of n -alkanes, pristane, phytane and presence of demethylated hopanes (25-norhopanes), it was determined that the original oil is biodegraded. Detecting n -alkanes, pristane and phytane (more susceptible to biodegradation), along with 25-norhopanes (less susceptible to biodegradation), suggests that the crude oil analyzed is the result of mixtures of several episodes of charging and biodegradation in the reservoirs. In crude oil after 90 days of the bioremediation test, the following order of biodegradation was found for the extended hopanes (R + S): C 35 > C 34 C 32 > C 31 . The change in the distribution of the extended hopanes related to the original oil indicates a greater alteration of C 32 and C 35 , and in the 22S and 22R isomers, a selective degradation for C 33 22S. Alteration of tricyclic terpanes is suggested, due to the variation in signal intensity in the original oil and that determined at 90 days. At the end of the test no alteration in steranes was observed, with only variation in signal intensity that suggests decreased concentration of these compounds. During the bioremediation test, n -C 25 , and pristane and phytane isoprenoids. Additionally, tricyclic terpanes, extended hopanes and steranes were altered.