Immobilization technology is of potential in industrial application for improving activity and stability of biocatalyst in nonaqueous systems.Alginate-chitosan (AC)microcapsules as immobilization carrier were prepared by emulsification-internal gelation and complexation reaction，and five solvents were selected to form culture medium-solvent two phase systems.At simulating yeast culture condition，AC microcapsules were put into the two phase systems and oscillated for 48 h.The morphology of AC microcapsules had no change for different two phase systems.For culture medium-dibutyl sebacate system，molecular weight of chitosan and formation time of microcapsule membrane were varied in a range of 40000—100000 and of 2—5 min，respectively，AC microcapsules with stable size，low broken rate and high mechanical strength were produced at conditions of low Mw (40000)chitosan and long formation time (5 min).These results showed that AC microcapsules prepared with above condition could be applied as immobilization carrier of biocatalyst.Moreover，yeast cells with biotransformation ability was used as a model of biocatalyst and entrapped in AC microcapsules.The growth of yeast cells entrapped in AC microcapsules to produce 2-phenylethanol was investigated in the culture medium-solvent two phase systems.The results showed that entrapped cells still keep its activity and can normal grow，which means that two phase systems have no adverse effect on it.Therefore，the immobilized yeast cells are of high biotransformation ability in the culture medium-solvent two phase systems with substrate concentration of 8—16 g·L-1.