Production of beta-galactosidase from by-products created by the dairy industry

Abstract

Due to the high concentration of lactose, proteins and minerals dairy by-products have a high chemical oxygen demand, which may cause several problems for the environment when discarded improperly. Aiming at the reduction of its polluting potential, previous studies used this highly nutritive environment for the production of bio-products such as ethanol and biomass. For this it was used the Kluyveromyces marxianus yeast and wild yeast isolated from Gorgonzola cheese whey, in a culture environment containing whey fortified with yeast extract, (NH4)2SO4, ZnSO4, MgSO4 e K3PO4. The fermentations were carried out in anaerobic, microaerobiose and aerobically conditions for 24 hours, with results not significantly diverging in accordance with agitation. Furthermore, the whey comparison between fresh and whey permeate highlights the cheese whey in nature as more suitable for the production of biomass. In this project, is intended to analyze the influence of the culture environment in the production of ²-galactosidase by cells of Kluyveromyces marxianus. It will be carried out analysis of Lactose, cell growth, pH, enzymatic activity and chemical oxygen demand. The extraction of the intracellular enzyme is performed by autolysis of the yeast cells, using chloroform. It is expected, therefore, to obtain an intracellular product (the enzyme) and extracellular (yeast) in the same bioprocess in addition to the alcohol production (which is not the scope of this study) and reducing the environmental impact caused by the industry.