Optimization Of Fermentation Producing L-proline By Corynebacterium Acetoacidophilum

L-Proline is one of 20 basic amino acids involving in biology protein composition.It is widely used in medicine,agriculture,chemical industry and food..In the early 1990s,Stailake Bioscience Co.Inc Zhaoqing Guangdong began to obtain L-Proline by microbial fermentation.The process has been improved.But a few problems still exist,To solve these problems,the methods of persvation strian seed,contation of fermentation in batch,feeding method of fermentation,method of adding precursor would be reseach.The results are as below:The key condition of persvating work strains is temperature,under ultralow t-Emperature,the strain on agar or spending in 20 glycerol would keep its character in a longer period,test revealed a period of360 days.And in the commercial process,the frequency of rejuvenation an islation will drop to once in 6 months,which decline the cost of labor force then once a month in the past.It found that starch hydrolysis products are the best carbon source.Concentration of100g·L^-1 of starch hydrolysis products and 40g·L^-1 L-glutaminecouldbe converted into69g·L^-1L-proline.Corn steep liquor is the best instant nitrogen source,10g·L^-1corn steep liquor combine with 5g·L^-1silk peptide powder will be better.It will obtain a concentration of L-proline 71.1g·L^-1.In the procedure of fermentation,initial concentration of reducing sugar prefer80g·L^-1.The feeding glucose(keep the concentration in 30-40g·L^-1),urea is the best choice to regulating the pH in a suitable range,which successfully avoid”ammonia shock”.It will obtain a concentration of 112g·L^-1 L-proline,by fermenting 75h in a 50L fermentor.Adding precursor,L-glutamine,can obviously raise the productivity,and promote to produce L-proline.The best to adding precursor is the rapid growth period.At the first 8 hour is prefered.Monosodium glutamate would make a osmotic pressure in fermentation broth.So the concentration under 60g·L^-1 wouled be better.