| Fructooligosaccharides(FOS),also known as fructo-oligosaccharides or sucrose oligosaccharides,are formed by combining 1-3 molecules of fructose with β-(2-1)glycosidic bonds at the C1 position of the fructose residue of sucrose.Oligosaccharides,prebiotics with many health benefits.Compared with the traditional enzymatic method for the production of oligofructose,the fermentation method has the advantages of low cost,good benefit,low pollution risk,high productivity and high stability.In this paper,the fermentation method is used to produce oligofructose.High-yield Aureobasidium pullulans is a fermentation strain,and sucrose is used as a fermentation material to optimize the fermentation conditions to increase the yield of fructooligosaccharides.Then,using molasses as a raw material,the fermentation of A.pullulans and Angel Saccharomyces cerevisiae is studied.The impact of the study was conducted.The main results are as follows:(1)After preliminary screening and re-screening,high-yield strains of fructooligosaccharides were obtained,namely IPE-1,IPE-3 and IPE-5.After further screening in the fermentation tank,IPE-1 oligomerization The peak value of fructose is 103.57 g/L,the peak value of IPE-3 oligofructose is116.62 g/L,and the peak value of oligofructose is 110.91 g/L,so IPE-3 is used as the fermenting strain of fructooligosaccharide.(2)The effect of dissolved oxygen DO(fermentation speed,aeration volume and tank pressure)and temperature on the production of oligofructose in IPE-3 fermentation was studied in detail.The yield is higher under 35℃ and 35℃,and the effect of fed-batch fermentation on the yield of oligofructose was further carried out.During the fed-batch fermentation,the maximum oligofructose concentration was obtained in 60 h under the condition of maintaining the DO value of 5%.548.3±37.4 g/L and68.6±2.6%(g FOS/g sucrose)yield,and it was found that the DO value has little effect on the total concentration of oligofructose,but for the composition of oligofructose,especially in the fermentation broth The high degree of polymerization of oligofructose has a significant impact.After 12 hours of fermentation and culture,the ratio of fructotriose and sucrose tetraose in fructo-oligosaccharides steadily decreases,and the high degree of polymerization of fructo-oligosaccharides begins to increase.(3)Connecting the membrane(300KDa)to the fermentor to carry out the research of fed-batch fermentation under the membrane bioreactor,the concentration of oligofructose decreased instead,and the highest concentration of oligofructose was 320.21g/L.The fermentation of Angel Saccharomyces cerevisiae and the fermentation under different ratios of sugar were studied.The production of fructooligosaccharides will increase the glucose content,and the glucose is not easy to separate by membrane.The use of Angel Saccharomyces cerevisiae consumes glucose,and Angel Saccharomyces cerevisiae is in anaerobic Under the conditions,the consumption of glucose is faster than fructose.Fermentation with sugar cane molasses as raw material,and inoculation with A.pullulans and Angel Saccharomyces cerevisiae for fermentation.It was found that the initial access to Angel Saccharomyces cerevisiae would reduce the production of oligofructose.The fermentation tank was further used for fermentation,and sugar cane molasses was used as the raw material.The growth and proliferation of A.pullulans cells was hindered,and the cell concentration did not increase significantly as when sucrose was used as a raw material.Fructooligosaccharides were fermented with cane molasses with a sucrose content of 204.13g/L,and the oligofructose was 118.60g/L at 12 h.58.10%(g FOS/g sucrose)yield.In the yeast shake flask fermentation of sugar cane molasses filtrate,the purity of oligofructose increased by 13.33% within 24 hours of fermentation time. |
