Chapter 42 



Mechanisms in the Microbial Oxidation 

 of Alkanes 



R. E. Kallio, W. R. Finnerty, S. Wawzonek 

 and P. D. Klimstra 



I 



t seems well established that the primary enzymatic attack 

 on alkanes by microbial action occurs at the terminal carbon atom 

 and results in the early formation of a fatty acid corresponding in 

 chain length to the alkane (1, 9, 10, 14) ). Rupture of the hydro- 

 carbon structure and introduction of oxygen into the molecule 

 could conceivably occur in at least two ways; dehydrogenation of 

 the alkane to an olefin followed by water addition to the double 

 bond or by hydroperoxidation of the alkane leading to the forma- 

 tion of an alkyl hydroperoxide. Since there appears to be evidence 

 for both mechanisms these are examined in the discussion which 

 follows. Space stricture dictates the brief and incomplete form of 

 the treatment. 



MICROBIAL HYDROPEROXIDATION OF ALKANES 



Formation of alkyl hydroperoxides involves incorporation of 

 atmospheric oxygen into the alkane molecule either directly or 

 through the participation of another peroxide the formation of 

 which, in turn, is dependent upon the presence of free oxygen. 

 That atmospheric oxygen is necessary for bacterial alkane oxida- 

 tion has been shown indirectly by Hansen and Kallio (5) who 

 showed that while strains of nitrate-reducing pseudomonads 

 readily oxidized alkanes aerobically the organisms were unable to 

 do so anaerobically in the presence of nitrate. Updegraff and 

 Wren (15) in a careful re-assessment of earlier work demon- 



*This research was supported by a grant from the National Science Foundation 

 and the Petroleum Research Fund administered by the American Chemical 

 Society. 



453 



