456 Marine Microbiology 



with the size of the groups bonded to the carbon atom carrying 

 the unpaired electron. Analysis of microbial alkane oxidation 

 literature indicates fatty acids, ?i-alcohols, and methyl ketones 

 predominate as identifiable products from n-alkanes of low 

 molecular weight (Cio or less). Acids, alcohols and esters are the 

 major products of microbial oxidation of )i-alkanes longer than 

 ten carbon atoms. The division of end products seems, in any case, 

 to be quite clear: methyl ketones but no esters are produced by 

 bacterial action on low molecular weight alkanes whereas the 

 reverse is true of high molecular weight alkanes. Possible relation- 

 ships between free radical equilibria, terminal alkane oxidation 

 and end products are shown in Figure 2, from the original sug- 

 gestion of Leadbetter and Foster (9). Hanls (6) on the basis 

 of sequential induction experiments with an alkane oxidizing 

 micrococcus concluded that methyl ketones did not lie on the 

 direct pathway of alkane oxidations and thus it is tempting to 

 speculate that the methyl ketones observed by Leadbetter and 

 Foster may have been the result of free radical equilibria rather 

 than "direct" products of alkane oxidation. It is equally con- 

 ceivable that methyl ketone formation is the major pathway 

 followed in microbial oxidation of certain short chain alkanes. 



Although 'peroxides" (4) have been detected in culture 

 fluids of bacteria utilizing alkanes, the nature of such peroxides 

 has not been established. Reduction of hydroperoxides by bacteria 

 has been reported by Updegraff, and Bovey (15) and Stewart 

 et al. ( 14 ) showed that 1-decyl hydroperoxide was oxidized by a 

 species of Micrococcus. These fragmentary indications stimulated 

 attempts to establish more firmly the role of hydroperoxides in 

 biological paraffin oxidation processes and led to the synthesis 

 of a series of 1-alkyl hydroperoxides (C12 to Cis) by treating the 

 appropriate alkyl methane sulfonate with HjO: ( 17 ) . Alkane oxi- 

 dizing micrococci grown in minerals-alkane media readily oxi- 

 dized all 1-alkyl hydroperoxides as measured by conventional 

 manometry. Results of a typical experiment in which intact cells 

 were tested for their ability to oxidize an alkane, the correspond- 

 ing 1-alkyl hydroperoxide, and other mono-terminally oxygenated 

 derivatives of the alkane are shown in Figure 3. No attempt was 

 made to assess the significance of rate differences since no satis- 



