Thermal treatment of cheese whey for determination of suitable conditions for β- galactosidase production by Kluyveromyces marxianus fermentation.

Abstract

In the last years studies have been made to find viable applications to the cheese whey due to the large volume produced daily and the environment pollution caused by the absence of an appropriate destination for it. Among many researches in biotechnological utilization of cheese whey came of its use as a substrate for fermentation aiming to obtain some products being one of those the b-galactosidase. This study had the objective to heat treat cheese whey to eliminate the contaminant microorganisms without modifying the stability of the protein structure. The cheese whey was heat treated with flowing steam for 3, 5, 10 and 15 minutes and with pressure for 3, 5, 10 and 15 minutes. After the thermal treatment a counting in plates was made in PCA growth medium and the protein precipitation was verified visually. The experimental results showed that the treatment under pressure is efficient to control de microbiological growth, but a huge protein precipitation happened. However the thermal treatment with flowing steam was efficient in the microorganism's elimination without visible protein denaturation. Thus, for the production of âgalactosidase we will use a thermal treatment with flowing steam.