Optimization Of The Fermentation Condition Of Single Cell Protein Production Through Mixed Fermention By Beet Molasses

To study the protein content of fermented products, five strains yeasts, namely Angel yeast, 1450 # wine yeast, Candida utilis, Candida tropicalis and Saccharomyces cerevisiae were used to culture in four different components designed mediums, respectively, to determine the optimum fermentation medium. After the strains were mixed to identify the protein products of mixed fermentation and to optimize the ferment condition. The aims were to provide a theoretical basis and to present for information of industrial production. The results showed that:1. With single factor and orthogonal design, we got the components of beet molasses medium as following: molasses 6°Bx, urea 2g / L, (NH4)2SO4 2g / L, KH2PO4 0.7g / L, pH 6.0.2. The four different components of the medium on the five strains of the total protein yield were significantly difference(P<0.05), and demonstrated that the best medium was the beet molasses culture.3. Mixed fermentation by 5:5,4:6,3:7,6:4,7:3 indicated that total protein of mixed 1450 # wine yeast and Candida utilis, 5:5, were significantly higher than others(P<0.05), and they got the highest rate of total protein.4.The single factor and orthogonal design experiments L16 (45) showed that the optimized culture conditions were as follow: the initial pH of culture medium was 7.0, the zymotic fluid cubage was 50 mL/250 mL, the rotational speed was 180r/min, and then cultured on the shaking table at 30℃for 48 h. Urder the optimized culture conditions, the yeast total yield was 7.49 g / L , which was 11.29% higher than that before condition.