Pectinase production from immobilized and free cells of Geotrichum candidum AA15 in galacturonic acid and sugars containing medium

摘要

Immobilization of microbial cells over agricultural residue is an approach to reduce the cost. In this study, cells ofGeotrichum candidumAA15 were immobilized on corncob and the effect of simple sugars on pectinase production by immobilized and free cells was investigated. The results indicated that the simple sugars, except for glucose, had positive effect on the pectinase production. Moreover, presence of galacturonic acid in the reaction mixture did not inhibit the pectinase activity. The data further revealed that the pectinase titers reached its peak in 5?h of cultivation and remained unaffected even after the addition of galacturonic acid. Indeed the titers were several folds higher when the immobilized cells were placed in galacturonic acid containing medium. Generally, galacturonic acid repressed pectinase production by the free cells. The study explored the advantages of immobilized cells for pectinase production as it did not exhibit the catabolite repression.