In the case of alkanes, mono-oxygenase attack results in the production of alcohol. Most microorganisms attack alkanes terminally whereas some perform sub-terminal oxidation. The alcohol product is oxidized finally into an aldehyde and finally to a fatty acid . The latter is degraded further by beta-oxidation. Different microorganisms exhibit different group specificities. For example, some grow on alkanes of six to ten carbons in chain length, whereas, others grow on long chain alkanes. Some of the oxygenases are encoded on plasmids and others on chromosomal genes. Subterminal oxidation apparently occurs in some bacterial species ( Markovetz and Kallio, 1971 ).