IMMOBILIZATION OF BREVIBACTERIUM CELLS FOR THE PRODUCTION OF L-GLUTAMIC ACID

Studies were performed to elucidate the optimal conditions (gel concen tration, bead size, initial biomass, storage period) for immobilizatio n of growing cells of Brevibacterium sp. (DSM 20411) in alginate and a gar gels and to evaluate the immobilized biocatalyst in batch mode, an d continuous mode in a packed-column bioreactor, for L-glutamic acid p roduction. The entrapped cells were also cultivated for twenty five da ys in five repeated batches (each batch lasted for five days). Maximum L-glutamic acid production in batch and repeated-batch modes was 7.4 and 8.7 mg/ml, respectively, with alginate beads, and 11.8 and 13.3 mg /ml, respectively, with agar beads. Under optimized conditions (flow r ate, initial cell loading), L-glutamate productivity was maintained wi thin a range 10-11 mg/ml for two weeks, in continuous mode, in a packe d column bioreactor with immobilized cells. (C) 1998 Elsevier Science Ltd.