Improvement of cephalosporin C production by Acremonium chrysogenum M35 in submerged culture with glass beads or silicone rubber

Abstract

Physical stimulation using a baffle or an impeller has been previously reported to improve cephalosporin C (CPC) production and cell growth. In this study, the effect of glass beads on CPC production in Acremonium chrysogenum M35 was investigated in baffled flasks along with the morphological properties of the culture. Addition of glass beads into the culture broth was found to significantly influence CPC production and cell growth of A. chrysogenum M35 in baffled shake flasks. CPC concentration increased about 30% when compared with baffled flasks without glass beads. Morphological changes such as the total perimeter and number of units, total number of differentiated hyphae or arthrospores, corresponded to varied CPC concentrations. Specifically, total perimeter and number of units increased by more than 10%. However, changes in pH had no relationship to CPC production or the number of glass beads. Pieces of silicone rubber were mixed into a 5 L bioreactor culture to assess any improvement of CPC production. Once added into the main culture, the production of CPC increased about 30% while values of dissolved oxygen (DO), which can be used to estimate oxygen transfer rate (OTR), were lower than main medium without silicone rubber. And dry cell weight was also increased about 10% when silicone rubber was added into a 5 L bioreactor.