Repeated-batch and continuous production of chitinolytic enzymes by Penicillium janthinellum immobilised on chemically-modified macroporous cellulose

Conidiospores of the fungus Penicillium janthinellum P9 were immobilised on polyurethane sponge and chemically-modified macroporous cellulose and cultivated for the production of chitinolytic enzymes in shaken culture, repeated-batch processes. The highest enzyme production (342 U l(-1))was obtained using the macroporous cellulose BR-L01T(70) (Biomaterial Co. Ltd., Japan); with this carrier cell leakage was negligible. The immobilised mycelium of P. janthinellum P9 was then used for repeated-batch and continuous production of chitinolytic enzymes and N-acetyl-beta-D-glucosamine in a fluidised-bed reactor (1.01 working volume). While the repeated-batch cultivation resulted in almost the same enzyme activity (338 U l(-1)) obtained in shaken culture, with the continuous operation a steady enzyme production of about 450 U l(-1) was reached and maintained for 168 h at a feed rate of 0.036 1 h(-1). At this feed rate, enzyme volumetric productivity and total N-acetyl-beta-D-glucosamine production were 14.76 U l(-1) h(-1) and 15.9 g, respectively. Carrier colonisation and hyphal growth were followed by observations under the scanning electron microscope. (C) 1998 Elsevier Science B.V. All rights reserved.