The regulation of secondary metabolism from Tolypocladium inflatum, a study on strain improvement in cyclosporin A productivity and its relation to growth and glucose metabolism
The fungal product cyclosporin A is a powerful immunosuppressive with antifungal activity produced as a secondary metabolite from ' Tolypocladium inflatum'. As its role in transplantation surgery increases, the demands on industry to improve yields intensifies. Mutants showing increased production are compared with strain, MS-1, the original strain for this work for glucose (dextrose) consumption and growth and a relationship with enzymes of the Embden-Meyerhof Pathway is investigated. Statistical analysis is performed to ensure significance. Classical methods of mutation and selection for strain improvement are utilized. Increased cyclosporin A-producing mutants display decreased glucose consumption and slower biomass build-up when compared to strain MS-1 (P < 0.001) suggesting a slower rate of growth supports higher production. Coarse control of the enzymes hexokinase (HK), phosphofructokinase (PFK) and pyruvate kinase (PK) in cell-free extracts of 'T. inflatum' was investigated. Decreased activities of HK, PFK and PK activity was observed in higher cyclosporin A-producing strains with probabilities of significance of <0.01 for HK and PFK and <0.05 for PK. A peak of activity early in the fermentation was also observed with probabilities of <0.01 that change by day in enzyme activity is significant for HK, PFK and PK. This suggests a decreased role by the EM pathway and the early establishment of the biochemical route for glucose catabolism.