Macroporous hydrogel prepared via aqueous polymerization induced phase separation toward in situ immobilization of yeast

Abstract

Yeast‐loaded open‐cell macroporous poly(acrylamide) (PAM) hydrogels are prepared by polymerization induced phase separation (PIPS) with potassium persulfate (KPS)‐yeast as a redox initiator in a polyethylene glycol (PEG) aqueous solution. The presence of PEG not only allows the sizes of both void and interconnected pores of the hydrogels controllable, but also enlarges the void. Which makes it possible to embed cells in situ and efficiently transport nutrients inside the hydrogels. Yeasts are herein used to form a redox pair with KPS to run the polymerization of acrylamide (AM) at a mild temperature (less than 31°C), avoiding the cell inactivation during the polymerization. The in situ immobilization causes a uniformly distribution and high immobilization rate (~100%) of yeasts in the hydrogels. The hydrogels are then used to ferment glucose to produce ethanol, exhibiting high fermentation efficiency of 68%. After 10 cycles, the yeast can still maintain 86% of the initial fermentation efficiency. The yeasts maintain 87% and 93% of the initial cell activity after 1 week store at 4°C in dry state and in yeast extract peptone dextrose (YPD) medium, respectively. This study demonstrates that an aqueous PIPS initiated by peroxide‐target cells is an effective platform to efficiently in situ immobilize cells in a hydrogel for high performance fermentation.