Separation,Purification Of Oligosaccharides Derived From Alginate And Jerualem Artichoke And Their Effects On Growth Of Probiotics

Because functional oligosaccharides are not digested and decomposed in the oral cavity,stomach,and small intestine,they can only be decomposed in the colon by beneficial bacteria such as Bifidobacterium,making them have more physiological functions than ordinary sugars and are therefore people widely concerned.Among them,alginate oligosaccharides were obtained from alginate,and enzyme hydrolysis is widely concerned because of its high efficiency,specificity and mild reaction conditions.Although the alginate lyase is widespread in nature,many of them can not be used for industrialization.In this paper,two strains with high viability of alginate lyase were screened out from decayed kelp for identification,and one of the strains was optimized for enzyme production.Then the alginate oligosaccharides were produced by the 5 L fermentor,and the column chromatography was used to separate and purify the fermentation broth.The high purity of the alginate derived oligosaccharides were obtained,and the bioactivity of the probiotics was compared.In addition,the oligosaccharide derived from Jerusalem artichoke is a kind of oligosaccharide extracted from Jerusalem artichoke.The oligosaccharides have both fruit type?Fn?and cane fruit type?GFn?.At present,only GFn type monomer is sold in the market,and the price is high,which hinders the study of the physiological function of different degree of polymerization monomers.In this paper,the oligosaccharides from Jerusalem artichoke were separated and purified by column chromatography,and the separation conditions were optimized.At last,the prebiotic effect of oligosaccharide three sugar?F3?and four sugar?F4?on the probiotics of Jerusalem artichoke were compared.The main research contents and results are as follows:?1?The alginate degrading bacteria identified in rotten kelp were identified as Bacillus.The optimal culture condition was 10 g/L sodium alginate,pH 7,culture time 44h,and culture temperature 30?.The alginate lyase activity obtained was 14.42 U/mL.The concentration of alginate oligosaccharide was 2.78 g/L in 5 L fermentor.At a flow rate of 0.2 mL/min,a sample volume of 4 mL,a sample concentration of 150 g/L,and an elution agent of 0.2 mol/L NH₄HCO₃ solution,at this time,The concentration of alginate oligosaccharide was 10.09 g/L,the concentration is about 3.64 times higher than that of the end of the fermentation.The optimum addition of alginate derived oligosaccharides to Lactobacillus bulgaricus and bifidobacteria were 2 g/L and 0.5 g/L respectively,which reduced the culture environment pH and promoted the proliferation of two strains.?2?In the isolation of oligosaccharides derived from Jerusalem artichoke,The optimal separation conditions using Biogel P-4 column were flow rate of 0.05 mL/min,loading volume of 2 mL,loading concentration of 100 g/L,and 5%ethanol aqueous solution.The best conditions for the separation using Biogel P-2 column were flow rate of0.05 mL/min,sample volume of 1 mL,loading concentration of 100 g/L,elution with 5%ethanol solution.On this basis,the secondary separation of oligosaccharides derived from Jerusalem artichoke resulted in a purity of 98%of the inulin-derived oligosaccharide F3 and a purity of 90%of F4.The optimum addition amounts of oligosaccharides,F3sugars,F4 sugars and polysaccharide to Lactobacillus bulgaricus and Bifidobacterium were 0.5 g/L.The stimulative effect of oligosaccharides,F3 sugar and F4 sugar on Lactobacillus bulgaricus and bifidobacteria were superior to glucose,and the culture pH values were reduced from 6.8 to 5.3 and 4.8,respectively.