Molecular composition of the gas chromatography amenable fractions of maya crude oil. a reference oil for microbial degradation experiments

Abstract

Maya oil constitutes a representative example of heavy sulphur-rich oils of increasing use in refineries which has been used as reference oil in the microbial degradation experiments performed within the MATBIOPOL project. A detailed study of the composition of n-alkanes, isoprenoid hydrocarbons, hopanes, steranes, polycyclic aromatic hydrocarbons, sulphur-compounds, carbazoles, phenols and alkyl carboxylic acids is reported in the present study. The distributions of these compounds indicate that the oil is geochemically mature and non biodegraded. However, the degree of thermal maturation does not reach the maximum geochemical conditions of hydrocarbon generation. The composition of these biomarkers also indicates that the oil originated from organic matter deposited in evaporitic environments. The content in phenols, carbazoles and other polar and acidic molecules may induce toxic effects in the microorganisms that may eventually increase the crude oil degradation rate upon spillage in coastal areas.