Study On Maduramicin Fermentation By Actinomadura Yumaensis

Maduramicin is a new type of polyether ionophore antibiotic, which can particularly kill and restrain coccidia - a kind of animal parasite which induce coccidiosis. As a widely used anticoccidial drug, maduramicin has a wide anticoccidial spectrum, and it is effective at a low dose rate of 5 mg/kg to prevent the infection of various species of Eimeria.The quantitative analysis method of maduramicin., the maduramicin production by Actinomadura yumaensis, and the method of extracting maduramicin from broth were studied in this thesis.Spectrophotometric analysis -method was respectively established for maduramicin quantitative measurement. First extracted maduramicin from the Actinomadura yumaensis mycelium using methanol; then made the maduramicin extracts react with vanilin, the reaction conditions were: 75℃, 20min; finally under 520nm light wavelength, using the spectrophotometer determined the absorbency of the maduramicin extracts, and the maduramicin concentration can be obtained by consulting the standard absorbency-concentration curve.The maduramicin fermentation was studied using Actinomadura yumanense strain in shaking flask. The results showed that the suitable conditions were: glucose 7 %, soybean powder 1.2%, cornsteep liquitor1.2 %, NaCl 0.3%, CaCO3 0.1%, K2HPO3 0.15 %, Fe2(SO4)3 0.015 %, the initial pH value of the media was 6.6, and the fermentation temperature was 34℃.The results of batch fermentation in a 3.7L ferrnenter showed that the stirring speed and aeration had obviously influence on the maduramicin production. The suitable aeration rate was 1.0wm, and the stirring speed should be controlled according following subsection: 300rpm in 0-60h period, 500rpm in 60~120h period, 600rpm in 120~192h period, the whole fermentation period was 192h. In these conditions, the maduramicin yield was 8336μg /ml.Two types of fed-batch processes were studied. Under the intermissive fed-batch process, the initial glucose concentration was 40g/L, and the feeding substrate was added in 10 times after 36h cultivation, the total amount of feeding glucose was 30g/L, finally the maduramicin yield was 9645μg/ml. Under the continuous fed-batchprocess, the feeding substrate was added with a even speed of 0,0056g(glucose) /L/min from 36h to 156h, and the maduramicin yield reached 10218μg/ml, which was 22.6% higher than that obtained under the batch process.A process of extracting maduramicin from fermentation broth was established. After pretreatment, the Actinomadura yumaensis mycelium was obtained by filtration or centrifugation. Under 50℃ let the mycelium autolyze 12h with agitation. By comparison, chose ethyl acetate as the extraction agent; under room temperature, with agitation, extracted the mycelium 8~10h, the maduramicin extraction ratio reached 98%. Finally by vacuum evaporation and crystallization, the maduramicin crystal could be obtained from maduramicin extracts.