Nitrogen Metabolism of Arachniotus Dankaliensis in Submerged Culture

SUMMARY

The growth profile of A. dankaliensis (Cast.) van Beyma was established in a glucose-asparagine medium. Utilization of asparagine during the different phases of growth was studied by paper chromatographic analyses of free amino acids in the filtrate and mycelium and of bound amino acids in buffer extracts of mycelia and the pattern correlated with the growth profile. It was observed that an active conversion of asparagine into aspartic acid, glutamic acid, alanine, serine and glycine was manifested as the growth proceeded. The latter amino acids were found to be the principal constituents of the buffer-soluble proteins. It was supposed that a specific utlization metabolism, catalyzed by specific enzymes, was operative in the system. To test this contention the fungus was grown with all the principal amino acids replacing asparagine in the glucose-asparagine medium. In addition, some unrelated amino acids and some inorganic compounds were also used simultaneously as nitrogen sources. Good growth resulted only in those media which had the related amino acids as a nitrogen source. This pointed to a specificity in enzyme makeup. This was further supported by the fact that the utilization patterns of two different strains of A. dankaliensis (GR-1, and P. roseus Kuehn) were closely similar and fairly stable. It was concluded that such metabolic specificity under a given condition could serve as a criterion for comparative studies.