Alkanes are ubiquitous in nature; they are formed both abioticly and bioticly. In biological systems, alkanes are produced from a wide range of organisms. The main pathway relies on an essential reaction that produces an alkane directly from an aldehyde precursor. This unusual reaction is mediated by a decarbonylase, which has been shown to contain a cobalt-porphorin[1] active site in the enzyme. The isolated decarbonylase is produced in the algae Botryococcus braunii. Other organisms that produce alkanes via this pathway include plants, mammals, and bacteria [2].  

[1] Dennis, M. and Kolattukudy, P.E., 1992, Proc. Natl. Acad. Sci 89, 5306-5310.
[2] Dennis, M. and Kolattukudy, P.E., 1991, Arch Biochem Biophys 287, 268-375.