IN THE UNITED STATES THE POPULARITY OF GREEK YOGURT HAS BROUGHT A DISPOSAL ISSUE FOR ITS BYPRODUCT, ACID WHEY. CURRENTLY ACID WHEY IS APPLIED AS FERTILIZERS, ADDED TO ANIMAL FEED, OR DISPOSED OF THROUGH COSTLY NEUTRALIZATION METHODS. STRAIN IS PLACED ON THE ENVIRONMENT THROUGH DISPOSAL AND ON THE DAIRY MANUFACTURER THROUGH ECONOMIC BURDEN. HOWEVER, THERE IS OPPORTUNITY TO UPCYCLE THIS BYPRODUCT AND TAKE ADVANTAGE OF ITS VALUABLE COMPONENTS INCLUDING VITAMINS, MINERALS AND SUGAR. THE MAIN SUGAR IN ACID WHEY, LACTOSE, CAN BE CONVERTED TO ACETIC ACID THROUGH FERMENTATION WITH THE YEAST BRETTANOMYCES CLAUSSENII. HISTORICALLY, WHEY HAS BEEN USED AS A BASE FOR BEVERAGES AND WELLNESS TONICS AND TODAY, BEVERAGES CONTAINING ACETIC ACID ARE BECOMING POPULAR AMONG CONSUMERS FOR HEALTH BENEFITS. FERMENTATION OF ACID WHEY WITH THIS YEAST, B. CLAUSSENII, HAS THE POTENTIAL TO CREATE NOVEL, DAIRY-BASED ACETIC ACID BEVERAGES. TRADITIONAL FOOD FERMENTATION YEAST, S. CEREVISIAE, DOES NOT HAVE THIS ABILITY TO FERMENT LACTOSE, THEREFORE B. CLAUSSENII IS AN IDEAL OPTION. HOWEVER, LITTLE INFORMATION IS AVAILABLE ON HOW TO PERFORM LACTOSE FERMENTATIONS WITH THIS YEAST OR ON HOW IT HAS THE ABILITY TO DO THIS.THIS PROJECT WILL STUDY B. CLAUSSENII IN LACTOSE FERMENTATIONS IN ORDER TO CHARACTERIZE ITS BEHAVIOR AND OPTIMIZE STANDARD OPERATING PROCEDURES FOR POTENTIAL DAIRY-BASED FERMENTATIONS. THIS WILL BE DONE THROUGH SCREENING YEAST AND FERMENTATION CONDITIONS WITH A SYNTHETIC LACTOSE FERMENTATION AND THEN THROUGH FERMENTATION OF ACID WHEY. MOLECULAR BIOLOGY TECHNIQUES WILL ALSO BE USED TO LOOK INTO THE GENOME OF B. CLAUSSENII AND DETERMINE HOW IT IS ABLE TO METABOLIZE LACTOSE, IMPORTANT INFORMATION NEEDED TO FURTHER CHARACTERIZE THIS ORGANISM'S ABILITY TO BE USED IN LACTOSE FERMENTATIONS. OUTCOMES OF THIS PROJECT WILL POSITIVELY IMPACT THE DAIRY INDUSTRY THROUGH UTILIZATION OF WASTE STREAMS AND EXPANSION OF THE MARKET THROUGH DEVELOPMENT OF VALUE-ADDED BEVERAGES.