Preliminary Inquiry Breeding And Optimizing Conditions Of Hyaluronic-producing Strains

Hyaluronic acid (hyaluronic acid, referred to HA) is a kind of polysaccharide, having regularly alternating units of N-acetylglucosamine and D-glucuronic acid linked by1,3-β-glycosidic bonds,which are widespread in the animal cells of various organizations, such as skin, bone synovial fluid, cartilage, eye vitreous and the cockscomb of rooster. HA has great molecular weight, which gives its high viscoelastic. Hyaluronic acid possesses an important function of water keeping, providing nutrition and skin smoothing, so it has been used extensively for medicine and cosmetics industries. The study which do research in industrial production for the purpose of the HA fermentation, began in the early1980s. At present, bacteria used in HA fermentation is generally the mutated streptococcus. The methods of mutation are ultraviolet radiation-treated, chemical mutagenesis-treated and so on. Streptococcus zooepidemicus highly demands for nutrition so that we must afford many growth factors to induce its secondary metabolism-hyaluronic acid. In addition, adding a certain amount of glutamate and arginine in the broth can improve the yield of hyaluronic acid.In this experiment, use the preserved Streptococcus zooepidemicus as the original strain, first UV mutation, and then Glu-type screening. Use Glu-type as experimental materials for fermentation. After fermenting, I purify HA with ethanol which concentration is90%, and then gain the rude production of HA by centrifugalism. In this experiment, I choose many kinds of amino acids (Arg, His, Lys, Cys, Met) and bases (A, G, T, U), determine the proportion between them, and optimize fermentation conditions in order to increase the production of hyaluronic acid. To the strains which we obtained conduct conditions optimization of nitrogen source, carbon source, temperature and pH.The results show that the best formula of these growth factors are Arg0.07g/L, His0.05g/L, Lys0.07g/L, CysO.Olg/L, Met0.05g/L, A0.05g/L, G0.06g/L, T0.05g/L, U0.07g/L. Wherein the optimal carbon source is glucose, generally, the dosage is30g/L, the nitrongen source is complex-type preparations, the temperature is controlled at35-37℃and the pH is adjusted to7appropriately.