Study On Fermentation Technology Of Nosiheptide

Nosiheptide belongs to steptomyces actuosus. Steptomyces have a special function in enzymatic produce. Looking for new steptomyces is an active field in steptomyce breeding. Based on the former work, the main works are focused on the breeding and fermentation technology of nosiheptide, getting high production strains, and using genetic methods to get better strains. We also used central composite design methods to optimize the fermentation conditions.The methods used were mutation, protoplast regeneration, and protoplast fusion in order to get high yield strains. Result produce the high yield strain 7#UN16. The yield of nosiheptide is about 2100μg/mL, 61.54% higher than the original one.Using protoplast fusion technology to deal with 7#UV, NTG UV-NTG and I3, we selected 50 strains after two fusions, and got 3 better strains. Fermentation yield of the highest isl579.5μg/ml, 69.57% higher than the original one (average production is 931.5μ/g/ml).Genetic methods were used in the attempt to get higher strains. The result shows that the ones which have VHB albumen produce much higher yields of nosiheptide than the original ones, and the regeneration of transformation strain is stable. The nine regeneration of transformation strains are 13.69% higher than the original one, and the nine integration strains are 106.41% higher than the original one.By using central composite design methods the fermentation conditions are optimized. Independent variables are three kinds of inorganic salts((NH4)2SO4 Na2SO4 NaCl). The yield of nosiheptide was a dependent variable. Linear or nonlinear mathematic models are used to estimate the relationship between independent variables and the dependent variable, therefore we get the better function:y = 987.4702+4421414X₁ +1016216X₂ + 21.428X₃ -116993X₁² + 387.818X₂² + 1269502X₃² -133.18X₁X₂ +920.535X₁X₂ -687071X₂X₃R=0.92604.The better conditions are (NH4) 2SO4( X1): 0.125%-0.3% Na2SO4(X2): 0-0.4% NaCL ( X3): 0-0.3%. Therefore the best experiment conditions can be obtained by central composite design and response surface methodology. The observed values agree well with the model's predicted values.