470 



Marine Microbiology 

 }jl O2 consumed 



150 



100 



50 



20 



40 



6 



80 



mi nuhes 



¥ig. 3. Respiratory activities of intact bacteria and cell free extracts. Ex- 

 perimental conditions: t^': 37° C; pH 7.1 (phosphate buffer, 0.05 M); ± 

 n-heptane 0.1 ml, ± pyocyanin 0.7 mg. 



the hydrocarbon dehydrogenase, as previously obsen^ed by 

 Jakoby (5) for the aldehyde dehydrogenase of P. fluorescens. 



The crude extracts contain a complete respiratory system 

 and in aerobiosis actively consume O2 in the presence of n-hep- 

 tane (Fig. 3). The respiratory activity of the extracts is low in 

 comparison with the intact cells (Table 4) and consistently 

 increased by the addition of either DPN or pyocyanin. This fact 

 confirms the role of DPN and pyocyanin in the transfer of hydro- 

 gen from heptane and suggests that the activity of cell free ex- 

 tracts is partly limited by the concentration of the electron 

 carriers. 



From these data, it is clear that the primary attack of the 

 alkane molecule consists in an anaerobic dehydrogenation coupled 

 with either DPN or pyocyanin. Moreover, the dehydrogenation 

 of 1-heptanol and heptanal by the extracts provides additional 

 evidence that these compounds are intermediates in alkane 



