Fermentation Process Studies For Pleuromutilin

Tiamulin, a semi-synthetic antibiotic derived from pleuromutilin, has been widely used in the prevention and treatment of chronic respiratory disease of fowl, swine pneumonia and swine endemic dysentery. It is also an alternative drug of the control of swine mycoplasma infection. Pleuromutilin is a diterpenoid compounds, mainly obtained by the microbial fermentation. The demand from market of pleuromutilin is great, while the domestic production capacity is relatively small. Therefore, in order to increase the fermentation yield of pleuromutilin, a simple fermentation process with lower oxygen consumption and higher yield has been discussed and developed in this paper.Firstly, the strain which could resist 2-deoxy-D-glucose has been got through the method of mutation breeding. The mutant strains could lift the inhibition of glucose on the accumulation of the product. Through the high-throughput screening of more than 5000 mutation strains, we have obtained the strain Pmh4023 with higher yield. The production of Pmh4023 reached 9423μg/ml and increased 60% compared with the original strain. Based on the experiments on individual factor, PB experiment and slope-climbing test, the culture medium was optimized and the optimal medium was achieved: glucose 6%, corn steep 2.5%, Soybean powder, 0.5%, soybean oil 3%, Ca(NO3)2 0.08%, composite yeast extract 0.4%, KH2PO4 0.1%, MgSO4 0.02%, NaCl 0.0125%. This paper studied on the effect of the Accumulation and mycelium growth systematically when the ventilatory volume and the dissolved oxygen are changeable under the condition of industrial scale. Based on fermentation physiological characteristics of new strains, low oxygen consumption characteristics made the ventilation rate decreased from 2200 m3 / h to 1600 m3 / h. Because lower air volume was needed, 50 m3 fermentor tanks have an increase in the volume at 5% on average. So the production yield of pleuromutilin and the efficiency of the equipment utilization had been improved.According to the Pulse carbohydrate supplement experiment result, initial glucose concentration was 40 g/l, the concentration of glucose controlled within 20 ~ 40 g/l. Growth of cell and accumulation of pleuromutilin is the fastest under above conditions. In this training mode, production of pleuromutilin is increased rapidly. In 240 hours, it reaches the highest at 17957μg/ml, the fermentation time has been deducted by 72 h.In the experimental design, through the study of supplementary method, a new fermentation process with the supplementary stay put technique has been developed. In this process, the discharge of each batch has been increase by about 5 m3, extending product integration time by 48 hours, improve the fermentation index.