Laser micropyrolysis provides important molecular data,on organic fossils such as coals, source rocks, oil shales and kerogen. In our laboratory, the micropyrolysis system refers to a laser and an optical device; a sample chamber and cold trap; and a gas chromatography coupled with mass spectrometer triple quadripole (LmPy-GCMS) to separate and detail the composition of molecular pyrolysis products. The goal of this work was to use laser micropyrolysis to acknowledge the chemical structure of Botryococcus braunni and Gloeocapsomorpha prisca microfossils. The obtained results showed that isolated Botryococcus to have predominance of alkene > alkanes > diene hydrocarbons from C8 to C20 as well as the absence of botryococcenes and methylated squalenes, which chemical composition was similar with race A and S, as it has been described in the literature. Laser pyrolysis of G. prisca showed the carbon number distribution of n-alkanes and alkenes similar to those observed in the pyrolysates from B. braunni however, with low amount of C20+ n-alkanes. It was also noticed a contribution of oxygenated compounds in Kukersite pyrolysis products. Therefore, the collected data from laser experiments can complement the information obtained from bitumen analysis and showed no correlation can be made between Botryococcus braunii and Gloeocapsomorpha Prisca. Also, the use of LmPy-GCMS can improve our studies in chemical characterization of small components in heterogeneous material, as well as an identification of specific biomarkers in isolated microfossils. (C) 2016 Elsevier B.V. All rights reserved.