Mechanisms in the Microbial Oxidation of Alkanes 459 



tion theory. First, so far as the writer is aware, the crucial isola- 

 tion and identification of an appropriate olefin has never been 

 accomplished in what appears to be anaerobic alkane oxidation. 

 Another difficulty lies in attempting to reconcile dehydrogenation 

 of paraffins with the elegant study of Leadbetter and Foster ( 9 ) 

 on the oxidation of ethane by P. methanica. In the presence of 

 methane P. methanica oxidizes ethane to acetic acid. Cultures 

 provided with hexadeuteroethane (and methane) yielded acetic 

 acid which was shown by mass analysis to have the structure 

 CD3COOH, thus eliminating ethylene (CD. = CD,) as an in- 

 termediate in the oxidation of ethane. Nevertheless, it does seem 

 significant that in Senez' study glucose-grown P. aeruginosa 

 cell extracts have no heptane dehydrogenase activity. Hex- 

 adecane is utilized for growth by the pseudomonad used by 

 Senez, but such cells are devoid of hexadecane dehydrogenase 

 (Senez, personal communication). 



Since a fatty acid with the alkane carbon skeleton unchanged) 



CH3-(CH2)i3-CH = CH2 Hexadecene-I 



\ 



CH3- (CH2)|4-C-0-(CH2)|4-CH = CH2 15-Hexadecenyl 

 •I palmitate 



CH3-(CH ),5-CH=CH2 Octadecene-I 



CH3 - (CH2) i4-C-0-(CH2)|g- CH = CH2 17-Octadecenyl 

 II palmitate (2-3) 



+ 



CH3-(CH2)i6-C-0-(CH2)i6-CH=CH2 17-Octadecenyl 



II stearate (1-2) 



+ 



CH3 -(CH2)i5 -C-0- (CH2)|6-CH = CH2 17-Octadecenyl 

 11 margarate (7-8) 



Fig. 4. Esters isolated from culture fluids of Micrococcus sp. grown at the 



expense of hexadecene-1 and octadecene-1 (12). Numbers in parentheses 



refer to proportional amounts of esters produced. 



