Pellet growth and penicillin fermentation using a porous inert carrier

Abstract

A carrier-supported mycelial pellet growth of Penicillium chrysogenum was applied to penicillin fermentation system in order to improve the productivity in a bioreactor. Among various carrier materials tested, celite 560 was found to be most effective for both spore adsorption and pellet growth. The growth of hyphae through the pore matrix of the beads showed strong anchorages and provided stable pellets during the fermentation. When celite particles entrapping spores were inoculated to the culture medium in the range of 0-10%(w/v) lactose, it was found that the specific growth rate, the final dry cell weight, and the final penicillin concentration were significantly increased from 0.02 to 0.03 $hr^1$, from 19 to 28g/l, and from 2100 to 3000 IU/ml, respectively. However, the specific penicillin production rate was found to be nearly constant, 1900 IU/g-cell-hr. From the stability test of carrier-supported mycelial pellets, nitrogen limitation in the medium was found to be effective for both the suppression of cell growth and the maintenance of cellular activity during the repeated replacement cultures.