Characterization of Dairy Waste Whey and Its’ Utilization for the Production of Ethanol

Abstract

The objective of this study was characterization of dairy waste whey and its’ utilization for the production of ethanol. Whey is a byproduct and not considered as a resource in many milk processing factories. Usually, it is discharged to rivers and surface water. The physiochemical characteristics of whey was determined by Lactoscan Milk Analyzer, Refractometer and Titration Methods. Dairy whey consisted of biological oxygen demand and chemical oxygen demand. It represents largely disaccharide sugar content which is known as lactose (0. 36 – 0. 48) g/mL and it could highly pollute the environment or water bodies. However, this whey waste was changed into ethanol by yeast strain,<i> kluyveromyces delphensis.</i> The experimental design was studied with central composite design to investigate the effects of significant factors including initial lactose concentration, yeast cell concentration, temperature and pH value on fermentation process. In the present work, the best operating conditions were found at 6.15g/L (initial lactose conc.), 10g/L (yeast cell conc.), 27^oC (temperature) and 5.5 pH value respectively. The maximum ethanol yield obtained from cheese whey was 40.4 % (2.5g/L). Functionally, ethanol was determined by Fourier Transmission Infrared with the help of Infrared correlation charts and moreover, its characteristic was investigated. As a result, cheese whey is a good resource for a production of ethanol.