Research On Fermentation Conditions Of Inosine

Inosine fermentation is a typical type of metabolic control fermentation. Yeast powder materials playan important role in the processe of fermentation. Exploring the characteristic of key regulatory factors andimportant factors affecting the production of inosine fermentation are the key of Increasing production.Penicillin, bacillus peptide antibiotics can interfere with the synthesis of cell wall in order to changethe permeability cell, which is beneficial to the release of the product. Join the suitable concentration ofpenicillin has certain role to increase production in the early or middle of fermentation. Join at4h of theearly time or30h of the medium time to is appropriate and the optimal concentration is29.5~34.5U/L. Inshake flask test, after joining penicillin, inosine production increased by10.71%in4h and20.93%in30h. The effects of the penicillin production to use in middle-late time is superior in the medium term. In50Lfermentor enlarge test we add27.5.0to34.0U/L of penicillin in4h, inosine fermentation production hasno significant difference with contrast; And we add29.5U/L of penicillin fermentation in30h, inosineproduction increased by11.69%. But bacitracin has no obvious promoting effect for inosine fermentation.By high-performance liquid chromatography method measuring the concentration of adenine contentin the fermented liquid fermentation process change, the results showed that the intracellular adenineincrease rapidly in logarithmic phase, then fall and keep in a relatively constant level, the change is in linewith bacillus subtilis growth process; Extracellular concentration of adenine is higher (about60mg/L) inthe culture medium after sterilization, rapid decline in early fermentation and gradually reduced to a lowerlevel, the middle is about25~35mg/L. Moderate levels of inosine accumulation of adenine in thefermentation process should be near27~33mg/L. About70%adenine class material in yeast powder after high temperature sterilization is released into the extracellular for available adenine class material;30%part still exists in yeast has not been released for delayed adenine. The delayed adenine class material isimportant factor to maintain the suboptimal dose level of extracellular adenine concentration. If yeastpowder quality is poorer and the adenine content is insufficient, we can add adenine adenine to thefermentation, and make its content reached normal around100mg/L for the need of fermentationproduction. Yeast extract is a kind of chemicals raw material that has rich adenine, so it can be used insteadof yeast, and it can improve the inosine production. When yeast powder dosage is3.3g/L and yeast extractis amount of4.14g/L, it can reach the highest production in shake flask fermentation. The productionincreased by8.00%than pure yeast powder as raw material, the ratio of yeast powder and yeast extract is4:6.Yeast powder was processed by gas explosion method (GE). It can promote the release of adeninematerial, the release rate was99.07%in the condition of high temperature and high pressure, whichincreased by32.37%over yeast powder. Inosine yield are improved obviously when fermentation materialuse GE powder instead of yeast powder in full or in part in shake flask fermentation. The yeast powder andGE powder dosage respectively were4g/L and4.5g/L, the total of raw materials is reduced by29.27%,but the yield increased by11.86%.Vitamins such as biotin, thiamine, riboflavin, niacin, and folic acid were respectively fed in thefermentation beginning24hour and42hour. The study results showed it can promote inosine fermentation.When the concentration of biotin were4mg/L though fed-batch method, inosine yield increased by12.35%.When the concentration of thiamine were2.0mg/L though fed-batch method, inosine yield increased by17.82%. When the concentration of riboflavin were50μg/L though fed-batch method, inosine yieldincreased by19.67%. The vitamins’ mixture was fed in50L fermentor though fed-batch method, which inosine yield increased by9.27%. The effect of Supplemented with folic acid and niacin for promotinginosine formentation is not obvious.Yeast precipitation was separated from suspension of yeast powder which was treated at121℃for20min. Shake flask tests were respectively carried out with yeast precipitation and yeast extract. Inosinefermentation yield is decreased obviously, When the yeast thallus were removed, which showed that theyeast thallus play an irreplaceable role in the fermentation. When yeast extract increased by10%, inosineyield reached a level corresponding with the original fermentation medium. It was named semi-syntheticmedium Ι. Yeast extract was fed in semi-synthetic medium Ι though fed-batch method, which couldsignificantly improve inosine yield. when appending the concentration of peptone were6g/L insemi-synthetic medium Ι, the inosine yield increased obviously.Which was named semi-synthetic mediumⅡ.Adding4g/L yeast powder in semi-synthetic medium Ⅱ enlarged the dimension in50L fermentor, Itappended yeast extract at38.02ml/h with auto-continuous addition technology when the fermentationbegan12hour, which inosine yield increased by15.73%.