Yeast encapsulation in nanofiber via electrospinning: Shape transformation, cell activity and immobilized efficiency

To realize encapsulation of living microbial cells and easily evaluation of cell viability after immobilization, the yeast cells were encapsulated in water soluble PAAm nanofiber by a facile and effective electrospinning technology. Firstly, the conductivity, shear viscosity and surface tension of PAAm/yeast electrospinning solution as a function of mass ratios of yeast/PAAm were investigated to determine the optimum solution condition for electrospinning immobilization. After electrospinning, it is interesting to note that the original ellipsoidal structure of yeast cells turns to oblate spheroid structure. To distinguish immobilization structure from the bead appearing during general electrospinning process, immobilization structure and bead structure were compared and analyzed by FESEM and EDX. Free cell activity, the immediate cell activity after electrospinning and cell activity for seven days storage after immobilization were evaluated by dying methods of CTC and methylene blue, respectively. The results show that encapsulation efficiency maintained at about 40%, and immobilized yeast cells remain active even after seven days storage, which provides a promising application prospect for electrospinning immobilization.