Immobilization of Saccharomyces cerevisiae on to acrylamide–sodium acrylate hydrogels for production of ethyl alcohol

Acrylamide/sodium acrylate (AAm/SA) copolymers, prepared by using various crosslinkers, were used in experiments on swelling, diffusion, immobilization of yeast cells (Saccharomyces cerevisiae) and production of ethyl alcohol. AAm/SA hydrogels were used for swelling and diffusion studies in the nutrient medium of the cells. The parameters of equilibrium swelling, maximum swelling, initial swelling rate, diffusional exponent, network constant and diffusion coefficient of the hydrogel/penetrant systems were calculated and evaluated. Yeast cells were immobilized onto the hydrogels by adsorption method during multiplication and ethyl alcohol production of the hydrogels was investigated. Swelling of AAm increased with the addition of SA and ethyl alcohol production increased with increasing SA in the hydrogels. The best system for immobilization is found to be AAm/SA hydrogels containing N,N′-methylenebisacrylamide as crosslinker.