BIOETHANOL PRODUCTION BY SOLID STATE FERMENTATION FROM CHEESE WHEY MIXED WITH BREWER'S SPENT GRAINS

Food by-products, whey mixed with spent grains are renewable resources which can be used as fermentation susbtrates for bioethanol production using selected Kluyveromyces spp. yeast strains. These food by-products have extensive results as wastes in food industry, are cheap and readily available sources and their use has also important benefit for the environmental protection. The ability of some Kluyveromyces spp. yeast strains (commercial starter culture and wild culture) to ferment the carbohydrates mixture from a complex fermentation substrate based on hydrolyzed brewer's spent grains and cheese whey was analyzed. Three brewer's spent grains (hydrolyzed) and cheese whey (heat treated) ratios (1: 1, 1: 2 and 2: 1) were considered in the study. Studies have shown that using an optimum combination of fermentation substrate, respectively hydrolyzed brewer's spent grains and heat treated cheese whey in ratio of 1: 2 have influence on yeast fermentation behavior and yield ethanol production.