Preparation of polymeric microcapsules enclosing microbial cells by radical suspension polymerization via water-in-oil-in-water emulsion

Polymeric microcapsules enclosing Saccharomyces cerevisiae were prepared by radical suspension polymerization via water-in-oil-in-water emulsion. Trimethylolpropane trimethacrylate and 2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile) were used as monomer and radical initiator, respectively. A culture medium with suspended yeast cells, monomer solution with the dissolved radical initiator, and poly(vinyl alcohol) aqueous solution were used as inner aqueous phase, oil phase, and outer aqueous phase, respectively. The influence of microcapsule preparation parameters on the viability of encapsulated cells and encapsulation efficiency was investigated. The radical polymerization process did not cause significant damage to encapsulated yeast cells. Decreased weight ratio of aqueous phase to oil phase resulted in increased encapsulation efficiency of the cells. The diameter of the microcapsules could be controlled by varying the agitation rate.