DEVELOPMENT OF AN IMMOBILIZED CELL REACTOR FOR THE PRODUCTION OF 1,3-PROPANEDIOL BY CITROBACTER-FREUNDII

Citrobacter freundii DSM 30040 immobilized on modified polyurethane ca rrier particles PUR 90/16 was used for continuous glycerol fermentatio n in an anaerobic fixed bed reactor with effluent recycle and pH contr ol (fixed bed loop reactor). The fermenter was run with buffered miner al medium under growth conditions resulting in the permanent renewal o f active biomass. The effects of glycerol concentration in the feed, d ilution rate (D), pH and temperature (T) were investigated to optimize the process. With 400 mM glycerol in the feed, pH 6.9, T= 36 degrees C and D = 0.5 h(-1) the maximum productivity could be determined as 8. 2 g/l per hour of 1,3-propanediol.