Optimization And Application Of Liquid Medium On Compound Bacteria Culture Of Cows

In this paper, the optimum carbon source and nitrogen source and its optimal concentration were determined through the single-factor test by taking Saccharomyces cerevisiae, Candida utilis , Candida tropicalis as zymophyte. Moreover, the optimal carbon nitrogen ratio, inorganic salt concentration and culture conditions were determined by using L9 (34) orthogonal test. The optimal medium formula: glucose1%, molasses 7°Bx, Ammonium Sulfate 1%, yeast extract 3%, KH2PO4 0.3%, MgSO4 0.04%, CaCl2 0.02%. The optimal condition: temperature 30℃, pH5.0, speed 180r/min, inoculum size 7%.Yeast autolysis conditions were preliminary explored by mixing the three strains of yeast fungus according to certain proportion access to solid medium fermentation. By using orthogonal design L9 (34), optimal autolysis condition: emperature 50℃, pH5.5, NaCl 3%, autolysis time of 24h.The best solid-state fermentation process was selected through the comparison of different solid-state fermentation process. Fermentation was carried out as follows: aerobic fermentation for 24h at30℃, began to anaerobic fermentation and gradually heat up to 55℃, and then to maintain the conditions of 12h. The highest content of active substances of cultures was achieved under this condition and Oligonucleotide peptide reached 8.53mg/g and Amino acids reached 213.29mg/g.Cow feeding trial showed that test team had increased in daily milk yield of 1.07Kg/D per cow (p>0.05), and in somatic number reduction rate increased by 10%, the butterfat percentage was increased by 0.08% (p>0.05). Adding the compound yeast culture showed a positive effect in improving milk yield and reducing somatic number.