Study On Screening And Fermentation Process Of Dominant Strain Of Bifidobacterium Selenium-enriched

Bifidobacterium is an anaerobic gram-positive bacterium isolated from breastfed infant faeces by French scholar Tissier in 1899.Bifidobacterium is a dominant bacteria group with probiotic effect in human body,which plays a very important role in maintaining and improving immunity,promoting human body development,delaying body aging,and anti-tumor.Bifidobacterium has become one of the important indexes of human health.Selenium is a necessary trace element in human body and has the effect of interfering with various kinds of cancer.Inorganic selenium,organic selenium and elemental selenium are the main forms of selenium,organic selenium,elemental selenium and no selenium The bioavailability of machine-selenium decreased in turn,while the toxicity increased in turn.In addition to the characteristics of low toxicity and high bioavailability,microbial transformation of selenium products also has a series of beneficial effects for human beings,so the development of Bifidobacterium selenium-rich has great prospects.In this paper,Bifidobacterium selenium-enriched bifidobacterium was screened and cultured at high throughput.The inorganic selenium in the medium was transformed into organic selenium by using the physiological metabolic characteristics of Bifidobacterium.longum,and the higher bioavailability of Bifidobacterium selenium-enriched bifidobacterium was obtained.Through the optimization of fermentation conditions in 7L tank and freeze-drying conditions,Bifidobacterium selenium-enriched Bifidobacterium with high selenium protein content was obtained.Firstly,a rapid and efficient screening technique for high throughput of Bifidobacterium selenium-rich was established by using 96 hole deep hole plate microculture and enzymatic detection.A strain XBL-20 of Bifidobacterium selenium-enriched strain was screened by combining the primary screening with double screening and flask test.Compared with the original strain,the number of live bacteria in shaking flask fermentation was increased by 3 times,the number of live bacteria in pot fermentation was increased about 4.4 times,and the multiple passages could be maintained at a higher level of live bacteria.Secondly,Bifidobacterium selenium-enriched bifidobacterium with high selenium protein content was obtained by optimizing the fermentation seeds,culture conditions of fermenting medium in 7L tank,freeze-drying conditions and sodium selenite addition conditions.After three batches of continuous fermentation,the content of selenium-rich Bifidobacterium was more than 85%.