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

Abstract

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- β- d-glucosamine in a fluidised-bed reactor (1.0 l 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 l h −1. At this feed rate, enzyme volumetric productivity and total N-acetyl- β- 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.