Immobilization of fungus Aspergillus sp by a novel cryogel technique for production of extracellular hydrolytic enzymes

Aerobic cells of a fungus isolate Aspergillus sp. CX-1 have been immobilize d in macroporous cryoPAG and in different composite cryoPAGs - fibrous adju nct carriers. The productivity of the extracellular enzymes (exo-1.4-beta-g lucanase, endo-1.4-beta-glucanase, beta-glucosidase and xylanase), and the viability, growth and ultrastructure of the immobilized fungus have been st udied. The enzyme activities and stability during long-term repeated batch cultivation in the immobilized fungus were higher than in free mycelia when batch cultivated. The fungus immobilized in the composite cryoPAG, contain ing polypropylene non-woven fabric, possessed the highest exo-1.4-beta-gluc anase activity, the longest durability of enzyme production (85 days) and t he most reliable mechanical strength. The fungus immobilized in porous comp osite cryogel possessed a variety of advantages including easy control of c ryogel porosity, improved mechanical strength and durability, simplicity of construction, high enzyme productivity and high stability. (C) 2000 Elsevi er Science Ltd. All rights reserved.