Optimize The Fermentation Process Of Small Fermentor For Diosgenin Production By Dioscorea Zingiberensis Endophyte SYt₁

Yam diosgenin is the main raw material for the synthesis of steroid hormone drugs,and the method of traditional producing diosgenin had many problems,such as raw material drying up,serious environmental pollution.Our laboratory screened a strain of endogenous bacillus licheniformis SYt₁ from the rhizome of dioscorea zingiberensis C.H.Wright that would produce diosgenin,and the fermentation characteristics and the process of separation and extraction diosgenin has carried on the preliminary exploration,that provided a new idea for producing diosgenin,but the yield of diosgenin cannot achieve industrialization level,and further optimization the process of the small fermentor fermentation.This paper had optimized the medium of SYt₁ fermentation producing diosgenin in 5 L fermentor,on the basis of orthogonal design established experiment scheme and carried out the experiment,using Matlab software established the fermentation process model,and studied the fermentation kinetics model and the optimal pH control strategy in the process of fermentation.screened the optimal operating conditions to improve the yield of diosgenin that provided the basis for realization the magnification pilot of the microorganism fermentation producing diosgenin.The main research contents and results were as follows:?1?Single factor experimentSingle factor method was selected industrial fermentation commonly nitrogen sourcesoybean cake to replace peptone on the original fermentation medium.?2?Orthogonal designAccording to the L₉?3⁴?orthogonal table designed the experiment scheme about sugar,CaCO3,NaCl,soybean cake the four important component in the fermentation medium and completed the experiment,offline measured the fermented liquid sugar concentration,the concentration of bacteria and the yield of diosgenin in different time point,and the characteristics of SYt₁ small fermentor fermentation were studied.?3?Fed-batch fermentationThe strategy of SYt₁ fed-batch fermentation had preliminary explored,and discovered that constant feeding was the optimal feeding way,but the optimal rate of feeding need to further study.?4?Builded optimal pH control strategy of SYt₁ fermentation processAccording to the model of fermentation kinetics,calculated the product in fermented liquid accumulation rate change over time in different pH conditions,by setted the highest objective function of product generation,in the Matlab written computer program,final computation obtained the optimal pH control strategy for the corresponding objective function of SYt₁ fermentation process.?5?Validated the optimal pH control strategyIn order to demonstrated the validity of the optimal pH control strategy,that had done the optimal pH control of product generates in small fermentor of the SYt₁ fermentation process,the change of the parameters in the fermentation process through sampling test,the results show that the experimental group compared with control group,the yield of diosgenin was increased 20.68%.