SECRETION OF INVERTASE FROM SCHWANNIOMYCES-OCCIDENTALIS

Invertase synthesis in Schwanniomyces occidentalis is regulated by cat abolite repression and is derepressed by raffinose and low concentrati ons of glucose. Efficiency of a carbon source in derepression of inver tase is dependent upon the type of culture medium: either raffinose in a rich medium or a low concentration of glucose in a yeast minimal me dium. The kinetics of derepression can be modulated by changing the ca rbon source. When cells are grown in a rich medium with 0.5% raffinose as the sole carbon source, Schwanniomyces occidentalis secretes 80 ti mes more invertase than Saccharomyces cerevisiae grown in the same con ditions, About 50% of the total amount of invertase produced by Schwan niomyces occidentalis is secreted in the extracellular medium in contr ast to Saccharomyces cerevisiae where only 6 to 15% of the protein is secreted in the medium.