DEVELOPMENT OF A METHOD FOR IMMOBILIZATION OF NONFLOCCULATING CELLS IN LOOFA (LUFFA-CYLINDRICA) SPONGE

Both the matrix structure of loofa sponge and the flocculating propert y of cells were necessary for efficient immobilization. The addition o f chitosan to a reactor containing a bed of loofa sponge and a Candida brassicae cell suspension induced cell flocculation and the cells wer e efficiently immobilized. During ethanol production by the immobilize d cells, the free cell concentration in the broth was controlled at th e desired level by intermittent addition of chitosan to the reactor Th e immobilized cell concentration increased but their specific ethanol productivity decreased with an increase in the chitosan concentration. The maximum ethanol productivity was obtained at a low chitosan conce ntration of 0.03 g/litre. With this optimal concentration, the cell co ncentration, ethanol yield and productivity were, respectively, 2, 1.3 and 3 times higher than those of the suspension culture. Copyright (C ) 1996 Elsevier Science Ltd.