PRODUCTION OF CONCENTRATED BACTERIOCIN SO LUTIONS IN HIGH CELL-DENSITY BIOREACTORS

Bacteriocins are natural proteinaceous antimicrobial substances produc ed by microorganisms like lactic acid bacteria to dominate the other m icroflora. Their use in the food industry as natural preservatives is tightly linked to the emergence of efficient and inexpensive productio n and purification procedures. The production of an anti-listeria bact eriocin, named Divercin, by Carnobacterium divergens, has been studied in batch, continuous culture and with viable cells immobilized in alg inate gel beads retained in a plug flow bioreactor. The latter system gave the highest volumetric productivity with more than 10(5) AU L-1 h (-1), which was one hundred times the productivity of the batch system . A new simple (two steps) bacteriocin purification method was develop ed based on Triton -114 phase partitioning. The pilot production of ba cteriocin can then be achieved allowing the exploration of the impact of such additions on the microflora of foodstuffs. (C) Inra/Elsevier, Paris.