MODE OF UPTAKE OF INSOLUBLE SOLID SUBSTRATES BY MICROORGANISMS .2. UPTAKE OF SOLID NORMAL-ALKANES BY YEAST AND BACTERIAL SPECIES

By using two species of yeast and one of bacterium, evidence has been obtained which indicates that the microbial uptake of solid alkane powders occurs primarily through a substrate solubilization mechanism. EDTA, a strong inhibitor of hydrocarbon solubilization by the cells, inhibited the growth of these organisms on alkane powder; the inhibition could be removed via a supply of artificially solubilized alkane. One of the yeast strains, which was a mutant incapable of growing on solid alkane powder and liquid alkane, could grow very well on artificially solubilized alkanes. It was demonstrated that the solid alkane solubilization rate during microbial growth could satisfactorily account for the maximal alkane uptake rate actually observed during growth. The specificity of solubilization for the solid alkane used as the growth substrate was demonstrated.