The Screening Of Human-derived Butyric Acid Bacteria And Effect Of The Strain Metabolic Activity

Human probiotics are a kind of active microorganism which is beneficial to human health.It is derived from the human body and can regulate micro-ecological balance in the human gut.Butyric acid is an important material of normal colon cell growth,and energy source for cell differentiation fast.Butyric-producing acid bacteria in human gut has been confirmed that has an important role on human health.These butyrate-producing bacteria can provide energy for human intestinal epithelial cells and could significantly improve human immunity.Butyrate-producing microorganisms were identified through the perspective of morphological and molecular biology.Meanwhile,in vitro fermentation characteristics of isolates were analyzed.In this study,the microorganisms in faces of healthy human were isolated through plate separation process,and identified by 16S rDNA sequencing.Among them,Clostridium bifermentans are 9:TK6,B5,B8,B9,B11,C1,J5,J6,J9;and Clostridium butyricum are 2:TK16,TK17.The paper is determination of the changes of acids,enzymes and fermentation characteristics of C.bifermentans TK6 and C.butyricum TK16.Research on these two bacteria use fermentation characteristics of different multifunction oligosaccharides.Experimental methods have high performance liquid chromatography(HPLC)method,and high performance gas chromatography(HPGC).The results show that strian TK6 and TK16 all can use of seven kinds of oligosaccharides in fermentation,and produce acetate,butyrate,lactic,protease,xylanase,and KIC.In addition,the strain TK6 also can produce propionic acid,isobutyrate,isovalerate and isocaproicacid,cellulases.Isomaltooligosaccharide(IMOS)significantly promote the growth of strain TK16 and TK6.In the same process of vitro fermentation,using IMOS as the sole carbon source,the strain TK6 and TK16 have the largest counts.Viable counts of the strain TK6 is(5.97±0.16)×108 CFU/mL,and counts of the strain TK16 is(8.9±0.2)×107 CFU/mL.The strain TK6 and strain TK16 grew preferentially on IMOS,resulted(53.51±0.52)mmol/L and(19.58±0.78)mmol/L of butyrate,which was directed to produce the highest concentration of butyrate of all,respectively.Whereas the fermentation of FOS and XOS resulted the level of degradation were very low.In contrast to other oligosaccharides,fermentation of FOS by the type of strain TK6 and strain TK16 resulted in the highest production of lactic were(17.99±0.36)g/L and(4.49±0.24)g/L,respectively.Fermentation of IMOS,XOS and FOS by the type of TK6 resulted in the highest cellulose,xylanase and protease activity respectively were(1994.84±254.52)U/mL,(135.86±1.82)U/mL and(47.99±2.34)U/mL.Fermentation of XOS and FOS by the type of TK16 resulted in the highest xylanase and protease activity respectively was(2.5±0.04)U/mL and(50.74±1.82)U/mL.The optimal conditions among the tested for strain TK6 and strain TK16 were found to be 150 mmol/L L-leucine for 16 h at 37?,(8.18±0.06)mg/L and(6.23±0.75)mg/L,respectively.