Culture of yeast cells immobilized by alginate-chitosan microcapsules in aqueous-organic solvent biphasic system

Immobilization biocatalysis is a potential technology to improve the activity and stability of biocatalysts in nonaqueous systems for efficient industrial production. Alginate-chitosan (AC) microcapsules were prepared as immobilization carriers by emulsification-internal gelation and complexation reaction, and their contribution on facilitating the growth and metabolism of yeast cells were testified successfully in culture medium-solvent biphasic systems. The cell growth in AC microcapsules is superior to that in alginate beads, and the cells in both immobilization carriers maintain much higher activity than free cells, which demonstrates AC microcapsules can confer yeast cells the ability to resist the adverse effect of solvent. Moreover, the performance of AC microcapsules in biphasic systems could be improved by adjusting the formation of outer polyelectrolyte complex (PEC) membrane to promote the cell growth and metabolic ability under the balance of resisting solvent toxicity and permitting substrate diffusion. Therefore, these findings are quite valuable for applying AC microcapsules as novel immobilization carriers to realize the biotransformation of value-added products in aqueous-solvent biphasic systems