Intrinsic fermentation kinetic parameters of immobilized yeast cells.
Ryu-D-D-Y; Kim-H-S; Taguchi-H
Saccharomyces cerevisiae SC4126 immobilization within alginate gel particles was effected by mixing the cultured cell broth with sodium alginate and dropping the mixture into CaCl2 to prevent the gel particles from chelating phosphate. Fully activated 5 ml gel particles of immobilized yeast cells were packed into a differential reactor column and the initial reaction rate (determined in terms of the glucose assimilation rate) was obtained as a function of the superficial velocity flowing through the packed column. There was no change in the initial reaction rate when the superficial velocity was greater than 1.2 cm/sec and the effects of external diffusion limitation of the substrate were not significant. The apparent kinetic parameters determined experimentally varied markedly with the particle size of the gel containing the immobilized cells and an apparent modified Thiele modulus representing the degree of internal diffusion limitation. Using both a theoretical analysis of diffusion in the gel particles and an empirical determination of apparent kinetic parameters in the bulk phase, the intrinsic kinetic parameters of the immobilized yeast cells were estimated.