BIOREACTOR SYSTEMS FOR EFFICIENT PRODUCTION AND SEPARATION OF NISIN-ZUSING LACTOCOCCUS-LACTIS IO-1

Continuous fermentation was introduced to improve the nisin Z producti vity of Lactococcus lactis IO-1. Free cells showed a good productivity at the dilution rate of 0.1h(-1). However, nisin Z production was aff ected by cell wash-out at the dilution rate of 0.2h(-1). Continuous fe rmentation with the cells adsorbed on ENTG-3800 gel beads displayed an improvement in productivity at higher dilution rates. No enhancement of nisin Z production was observed during continuous fermentation at a high cell density employing a hydrophobic hollow fiber membrane. The polyolefin membrane adsorbed the produced nisin Z too much. Continuous fermentation at a high cell density employing a ceramic membrane disp layed a good nisin Z productivity at high dilution rates. Nisin Z prod uctivity could be increased if a ceramic membrane with an adequate and effective filtration area is employed. Nisin Z was separated from the fermentation broth using various kinds of adsorbents including Amberl ite IR-120B, CM Sephadex C-25, Celite, and Sep-Pak cartridges. The Sep -Pak (tC(18), C-18, C-8, and tC(2)) cartridges showed a substantial ca pacity for nisin Z adsorption. A moderate reversed-phase column, a Sep -Pak C-8 cartridge, was applied to integrate nisin Z fermentation with a ceramic membrane and product separation system. Nisin Z productivit y was enhanced by the integration of the nisin Z adsorption cartridge. This result indicates the possibility of continuous fermentation with the integrated bioreactor system followed by high nisin Z productivit y.