Optimization Of The Fermentation Medium And Fermentation Process Of Clavulanic Acid

Clavulanic acid is a kind of antibiotics which has the inhibitory effect of beta-lactamase produced from Streptomyces clavuligerus.This article is mainly optimized the culture media and fermentation process to improve the clavulanic acid production capability of Streptomyces clavuligerus strain.Firstly,the seed culture media and culture condition in the shake flask has been optimized.The optimal component of seed culture medium is（g/100mL）:corn starch2.0,superfine soy flour 2.0,yeast extract 0.5,triolein 0.5,KH₂PO₄ 0.1,pH 6.9.The superfine soy flour pressed at middle temperature is much better than others pressure technology for the seed growth.The seed culture conditions were studied.The initial pH of the seed culture is 7.0.The optimal inoculation quantity is 1.0%.The seed should be incubated for 60-66 h at 28 ^℃.Secondly,the fermentation medium in the shake flask has been optimized.As a replacement of the corn starch,the corn starch milk as the carbonsource caused an increase in the production and a drop in the cost.The addition of aspartate,glutamic,threonine and lysine in the medium is beneficial to the synthesis of CA.The optimum concentration of these animo acids is 0.02%,0.1%,0.05%and 0.1%respectively.However,the synthesis of CA will be strongly inhibited by the addition of methionine.The inhibition will be strengthened with the increase of the methionine concentration.The addition of potassium dihydrogen phosphate and ferrous sulfate has a significant effect on CA biosynthesis.The optimal concentration of them is 0.5%and 0.1%,respectively.Thirdly,the culture conditions in the shake flask were optimized,also.The initial pH of the fermentation culture is 7.0.The optimal inoculation quantity is 2.0%.The strain should be incubated at 25 ^℃.The optimal medium volume is 45 mL in 500mL shake flask.And the optimal shaking speed is 250 r/min.Finally,the culture conditions in the seed tank and the fermentation tank were optimized.The initial pH of seed tank is 6.8.The optimal inoculation quantity of the seed cultured in shake flask is 0.1%.The optimum concentration of soy protein powder,soybean oil and glycerol in fermentation medium is 2.2%,1.2%and 1.0%,respectively.The optimum inoculation amount of the seed cultured in seed tank is15%.After inoculated for 22 h,50%glycerol solution has been feedinged to the fermentation broth.The amount of residue glycerol is controlled from 1 g/L to 3 g/L.On the basis of the pilot experiment,the strain has been incubated in a 100m³fermentor.The titer of CA reached 7520μg/mL.The productin has been increased by24.3%.