Potential of 'coalho' cheese whey as lactose source for beta-galactosidase and ethanol co-production by Kluyveromyces spp. yeasts

摘要

The present study evaluated the co-production of beta-galactosidase and ethanol byKluyveromyces marxianusATCC 36907 andKluyveromyces lactisNRRL Y-8279 using as carbon source the lactose found on "coalho" cheese whey. Cheese whey was subjected to partial deproteinization, and physicochemical parameters were assessed. Cultivations were carried out in an shaker to evaluate two carbon/nitrogen (C:N) ratios. The best C:N ratio (1.5:1) was carried to 1.5-L bioreactor cultivation in order to increase co-production yields. The stability of beta-galactosidase was assessed against different temperatures and pH, and in the presence of metal ions. Concerning the co-production of beta-galactosidase and ethanol,K. lactisproved to be more efficient in both the C:N ratios, reaching 21.09 U center dot mL(-1)of activity and 7.10 g center dot L(-1)of ethanol in 16 h. This study describes the development of a viable and value-adding biotechnological process using a regional cheese by-product from Northeast Brazil for co-production of biomolecules of industrial interest.