Two novel cell immobilization supports, Zr(Ⅳ)-and Fe(Ⅲ)-loaded collagen fibers (ZICF, FICF), were prepared by loading Zr(Ⅳ) and Fe(Ⅲ) on collagen fiber. As an experimental model, the immobilization behaviors of Saccharomyces cerevisiae(S. cerevisiae) cells on ZICF and FICF were characterized, and consequently, the fermentation activity of the immobilized cells were investigated. The amount of cells immobilized on ZICF and FICF reached 6.68×10^7 and 5.44×10^7 cfu/g, respectively, when the immobilizing reaction was carried out by using 3.6×10^5 cfu/mL of S.cerevisiaecells at pH 6.0 and 30 ℃. Environmental pH did not substantially affect the immobilization of S. cerevisiae on ZICF. A maximal immobilization amount was achieved in 0.1 mol/L of NaCl solution by using the cells growing at stability phase. The immobilization (adsorption) equilibrium of ZICF to S. cerevisiae cells could be described by Freundlich model, while the kinetic process followed pseudo-second-order rate model. The immobilized S. cerevisiae cells on ZICF exhibited high ethanol productivity, yielding 9.1% (v/v) of ethanol in ethanol-fermentation culture medium containing 15% of glucose. In addition, the ethanol yield kept at 7.8% (v/v) even at 12th fermentation cycle, showing an excellent reusability of the immobilized S. cerevisiae cells.
