MICROBIAL ENZYME-PRODUCTION IN A MEMBRANE BIOREACTOR

Erwinia chrysanthemi cells were used to study the possibility of producing bacterial enzymes in a bioreactor coupled with a membrane filtration unit. Continuous fermentations with total cell recycle failed to give good production of pectate lyase (PL). Enzymatic, mechanical and physico-chemical damages were involved in this phenomenon. With a sequential recycle mode, we obtained productivity of 1.5 units.h-1.1(-1) with a high PL concentration. Protease accumulation occurred when the bioreactor was coupled to a filtration unit. Moreover we have observed no loss of activity due to high shear stress caused by pumping.