The Rate of Elaboration of the Extracellular Polysaccharide, Pullulan, during Growth of Pullularia pullulans

SUMMARY During the growth of the yeast-like fungus Pullularia pullulans, the pattern of glu- cose utilization by the cell varied from a complete inability to elaborate extracellular polysaccharide to the diversion of almost two-thirds of metabolized glucose to pullulan elaboration. The effects of carbon and nitrogen levels on this changing pattern during growth were examined. These investigations indicated that the elaboration of pullulan, and the onset of a morphological change of Pullularia from a filamentous to a yeast-like form, were related to the availability of nitrogen, and not carbon, in the growth medium.