Research On Glutathione Production By Fermentation With Soybean Whey

Soybean whey is wastewater during processing of bean products,it contains large amounts of whey protein,soybean oligosaccharides and other organic matters.If discharge it directly,it will cause environmental pollution and waste resources.By biological fermentation of soybean whey,bioactive substances will be producted,which will not only reduce the environmental pollution,utilize the waste water effectively,but also open up a new way for glutathione production.In this paper,the GSH production by soybean whey fermentation was studied,the yeast strain with high yield of GSH was breeded,and its fermentation conditions was optimized,the GSH was separated and purified.Firstly,we had chosen Candida utilis,Yeast,Candida tropicalis,KARs yeast to fermentate soybean whey for GSH production.Comparing with GSH yield rate,it was found that the GSH yield of Candida utilis is the highest.The mutant strains was breezed using Candida utilis as the original strain.The mutagenic conditions were:Ultraviolet mutagenic time is 120s,concentration of ZnCl2 is 2g/L.The strain C1 with high yield of GSH is obtained under the suitable mutagenic conditions.its yield increased by 79.2%.The study indicated that the heredity character of strain C1 was stable in consecutive cultivating 5 generations.In order to improve the yield of GSH,the fermentation conditions of soybean whey on high-yield strain C1 were studied.The results showed that in the volume of 60%,at 32?,inoculum 6%and 22h,the highest GSH yield reached 21.5mg/L,as increased by 36%.Furthermore,BOD5 and COD in the soybean whey was reduced by 54.9%and 32.1%respectively,but still can not meet the national standards for wastewater discharge.Finally,we studied the glutathione purification with ion exchange resin(001×7),and its purification conditions were optimized.The optimum conditions were as follows:pH of sample solution was 3.0,eluting with 3%HCl and elution velocity was 2mL/min.Under this condition,glutathione average recovery was achieved to 67.5%.The purity of GSH was determined to be a low purity by TLC,it needs further study.