Abstract: Background and Objective: Dairy wastes are sources of environmental pollution and efficiently used for production of added value products is an important issue. The aim of this study was to use milk permeate for production of Saccharomyces cerevesia biomass, as baker's and feed yeast. Materials and Methods: The fermentation process was conducted with 250 mL conical flasks in shacked cultures using different volume ratios of culture medium with different agitation rates (150 or 200 rpm) for achieving the aeration test. The effect of incubation time on the production of yeast biomass was investigated. Applying the optimum parameters in lab scale fermenter (7.5 L) were carried out. The produced yeast biomass was used in enrichment of the feeding value of lactating animal’s diets containing agricultural wastes. Results: The optimum parameters for the production of yeast biomass were using 1:10 ratio of fermented medium to the entire volume of the fermentation vessel (250 mL conical flask) which yielded at agitation rate of 150 and 200 rpm and a yield reached at 8.22 and 8.84 g L–1, respectively. The optimum incubation period was 72 h with yield reached at 9.12 g L–1. High biomass yield was produced in lab scale fermenter reached to a maximum level of 116 g L–1. When the produced yeast was added to dairy animal’s diets, the Dry Matter (DM), Natural Detergent Fiber (NDF), Acid Detergent Fiber (ADF), cellulose and hemicellulose degradability was increased, with no impact on ruminal total gas production and ammonia concentration. Conclusion: Hence, it was concluded that yeast biomass produced on permeate hydrolysate give high yield and improves the degradability of dairy animal’s diet.