Study of Bioethanol Accumulation in Dairy Whey Using Immobilized Yeast Cells

Dairy whey, that is a byproduct from cheese production, is not only an environmental challenge, but also an energy renewable enabler. This study investigates the accumulation of bioethanol in dairy whey using immobilized yeast cells. The aim was to test the ethanol production by the immobilized yeast cultures onto different sorbents. Yeast strains Saccharomyces cerevisiae AI1, Kluyveromyces marxianus AC1, and Rhodotorula lactose SR were employed singly and in co-cultures and immobilized onto sodium alginate, polyvinyl alcohol, and carrageenan matrices. Sodium alginateentrapped yeast cells lost their ethanol-accumulating power whereas polyvinyl alcoholand carrageenan-immobilized yeast cells exhibited good bioethanol productivity. The highest ethanol yields were attained from S. cerevisiae AI1 were 2.55% and 2.42% after 48 hours, while K. marxianus AC1 produced 2.25% and 2.62% under the same conditions. These results demonstrate that immobilized yeast cell technology offers a promising approach for sustainable bioethanol production from dairy industry.