Hyaluronic Acid Producing Bacteria Mutagenesis And Optimization Of Fermentation、Extraction Conditions

Hyaluronic acid is one king of acidic mucopolysaccharido which exists extensively in many tissues of human and animals. Hyaluronic acid is made up with D-glucuronic acid and N-acetyl glucosamine which are connected repeatedly by glyosidic bond β-1,4 and β-1,3. Because of its special physiological action and moister-holding function, it is widely applied for health food, cosmetic industry and medical domain.Streptococcus equines MF003 was used as an original strain to perform H2O2 oxidative stress culture, ultraviolet radiation (UV) and diethyl sulfate (DES) compound mutation. After screening, a hyaluronidase deficient strain ZD-25 with high molecular weight and high-yield of hyaluronic acid was achieved. Based on shake flask fermentation, the yield of hyaluronic acid reached to 1.61g/L and relative molecular weight of 2.13×106D. Compared to the original strain, the yield and relative molecular weight were increased by 120.5% and 57.8%, respectively. The production and relative molecular weight of hyaluronic acid maintained high stability after several generation of reproduction.Streptococcus zooepidemicus MF001 was used as an original strain to optimize the hyaluronic acid fermentation conditions. By selecting the type of fermentation medium of carbon sources, initial Glucose Concentration, nitrogen source, the choice of carbon source and nitrogen source. Finalize the choice of carbon source is glucose, the initial concentration of 60g/L; nitrogen source was yeast powder, carbon source and nitrogen source compared to 2.5 for the best fermentation conditions.Hyaluronic acid broth was fermented by Streptococcus zooepidemicus MF001 was used to extraction optimization. The traditional quaternary ammonium salt extraction method was instead of the combination of the suction filter membrane and activated carbon extraction method. Hyaluronic acid broth pH adjustment to 4.0, let stand for 1 h then back to 7.0. Extraction adsorbents used medicinal activated carbon, activated carbon dosage for 6 times the quality of hyaluronic acid, activated carbon processing temperature of 37℃, the processing time is 1 h. Activated carbon adsorption manner by mechanical stirring; Use 2 um of microporous membrane filter for filtering as the best condition.