Hydrocarbons and fatty acid methyl esters were identified by chromatography-mass spectrometry in the extracts from the native biomass of bacteria: chemoorganoheterotrophic Arthrobacter sp. and Pseudomonas aeruginosa and chemolithoautotrophic Carboxydothermus sp. Ultrasound treatment of bacterial biomass and mild thermolysis were shown promote formation of a broad spectrum of hydrocarbons from bacterial biomass. The biomarker stigmastane belonging to the sterane group was found in P. aeruginosa biomass after thermolysis at 110 degrees C in an open vial. Alkane composition in P. aeruginosa biomass before and after thermolysis at 300 degrees C in a sealed container remained unchanged, indicating the possibility of preservation of hydrocarbons of bacterial origin in sealed layers under high temperature and elevated pressure.