| This research has involved determining to what extent specific yeast strains typically employed in the food industry, utilize lactose and produce commercially useful by-products. Cheese whey is largely a waste product of the dairy industry which contains approximately 5% lactose, and its untreated disposal contributes a massive biological oxygen demand on municipal sewage treatment plants.;A variety of yeast strains were analyzed for their abilities to achieve the above objectives, and to characterize their growth under experimental conditions, their ability to utilize varied carbon and nitrogen sources, their morphology with electron microscopy, their response to antibiotics, and their DNA ultraviolet absorbance and denaturation curves. A comparison was made of the ;Attempts were made, with limited success, to obtain genetically-modified yeasts, by fusion processes and by transformation, to show greater activity in either lactose utilization or in by-product formation. While the techniques used were proven feasible, it was concluded that the pre-existing strain of K. fragilis (CBS 397, obtained from The Netherlands) showed the most efficient lactose utilization, and was the best butanediol and glycerol producer.;It was found that K. fragilis CBS 397 was a nonhalophilic yeast which only produced high glycerol levels when grown under anaerobic conditions, and optimum yields of glycerol only occurred in the presence of 1% Na... |
