IMMOBILIZATION OF CHITINOLYTIC ENZYMES AND CONTINUOUS PRODUCTION OF N-ACETYLGLUCOSAMINE WITH THE IMMOBILIZED ENZYMES

Chitinolytic enzymes containing chitinase and beta-N-acetylhexosaminidase (NAHase) from Nocardia orientalis IFO 12806 were immobilized on various carriers by different methods for the continuous production of N-acetylglucosamine (GlcNAc). The immobilized enzyme containing both enzymes prepared by physical adsorption to tannin-chitosan was very useful for GlcNAc production. The optimum pHs of the immobilized chitinase and NAHase on tannin-chitosan were shifted lower than those of the free forms. The optimum temperature of the immobilized chitinase decreased from 60-degrees-C for the free form to 40-50-degrees-C, although the thermostability of the immobilized form increased in comparison with that of the free form. As for NAHase, little difference was observed between the immobilized and free forms in optimum temperature and thermo-stability. In GlcNAc production using a column reactor packed with the immobilized enzyme, GlcNAc was continuously obtained from chitin-oligosaccharides with a yield of above 90% over 130 d. After the operation, the activities of immobilized chitinase and NAHase remained at 47.2% and 32.5% of the initial activities respectively.