Volume 6
Issue 1
Biotechnology
JOURNAL OF
POLISH
AGRICULTURAL
UNIVERSITIES
Available Online: http://www.ejpau.media.pl/volume6/issue1/biotechnology/abs-02.html
BIOSYNTHESIS OF DIVERCIN BY CARNOBACTERIUM DIVERGENS AS7 IN CONTINUOUS HIGH CELL DENSITY CULTURES
Anna Sip, W³odzimierz Grajek
ABSTRACT
Continuous cultures of Carnobacterium divergens AS7 with cell recycling were characterized with respect to their growth kinetics, fermentative activity and ability to biosynthesize the anti-listerial bacteriocin divercin. The experimental variables were dilution rates from 0.14 h-1 to 0.36 h-1 and a two-level recycling rate. The experiments demonstrated that dilution rate and cell recycling strongly influenced cell density in a bioreactor. With an increase in dilution rate, an increase in cell density was also observed. At D=0.36 h-1 the maximum cell density of 48 g d.m. l-1 was obtained. With long fermentation time and high cell density, the number of dead cells rapidly increased. In these experiments, when cell density increased 10-fold, the number of viable cells increased only 2-fold. It was found that divercin biosynthesis was reciprocally correlated to dilution rate. The greater dilution rate, the lower the volumetric productivity of
Key words: Divercin, Carnobacterium divergens, membrane bioreactor, high cell density culture.