本文選題：星狀雙歧桿菌 + 胞外多糖��； 參考：《中國農(nóng)業(yè)大學(xué)》2005年碩士論文

【摘要】：雙歧桿菌(Bifidobacterium)是人和動物腸道內(nèi)重要的生理性細菌,它的存在直接影響消化道的健康狀況。目前國外有關(guān)雙歧桿菌胞外多糖(Exopolysaccharides,EPS)研究的報道寥寥無幾,而國內(nèi)則處于一片空白�；诖搜芯楷F(xiàn)狀,立題于雙歧桿菌EPS,旨于為進一步開發(fā)新型EPS提供方向,并為研究雙歧桿菌生理功能的機理奠定基礎(chǔ)。具體展開了下列研究工作: 1)從大量樣品中分離篩選出一株具有較強產(chǎn)EPS能力的雙歧桿菌菌株22-5,菌株經(jīng)Biolog全自動微生物鑒定儀初步鑒定為星狀雙歧桿菌。經(jīng)回收率試驗確定苯酚-硫酸法為檢測此EPS的方法。 2)對星狀雙歧桿菌22-5產(chǎn)EPS的培養(yǎng)條件和培養(yǎng)基組成進行了優(yōu)化。結(jié)果表明,最佳培養(yǎng)條件為25℃恒溫厭氧培養(yǎng)24h且培養(yǎng)基初始pH值為5.5;通過單因素確定最佳碳源、氮源、刺激因子后采用三元二次回歸正交旋轉(zhuǎn)設(shè)計進行優(yōu)化。優(yōu)化后EPS產(chǎn)量達到1.21g/L,是初始培養(yǎng)條件下產(chǎn)量的6倍多。 3)對星狀雙歧桿菌22-5所產(chǎn)的EPS進行提取及分離純化條件的優(yōu)化,確定了提取純度高且EPS損失較小的方法路線,即:收集發(fā)酵上清液→濃縮→乙醇沉淀→脫蛋白→透析→Sepharose CL-6B凝膠層析。通過對Sepharose CL-6B瓊脂糖凝膠純化EPS條件的摸索,得到可洗脫下對稱單一多糖峰的條件:0.05M NaCl作洗脫劑,30mL/h的洗脫速度。采用UV和HPLC分析鑒定,證明此EPS成分單一,具有較高的純度。 4)經(jīng)HPLC法檢驗,得知菌株22-5 EPS的分子量為3.92×10~5Da。菌株22-5所產(chǎn)的EPS具有較高的粘度,其隨著溫度的升高粘度不斷降低,其粘度對酸和離子強度穩(wěn)定,但對堿不穩(wěn)定。此多糖對病原菌的抑制作用不明顯,對乳酸菌的生長有一定的促進作用;通過DPPH自由基的驗證說明其清除自由基的能力較強;可顯著增強菌株22-5對腸上皮細胞Caco-2的粘附作用。
[Abstract]:Bifidobacterium (Bifidobacterium) is an important physiological bacteria in human and animal intestines. Its existence directly affects the health of digestive tract. At present, there are few reports about Exopolysaccharide of Bifidobacterium Exopolysaccharide EPSs in foreign countries, but there is a blank in our country. Based on the present situation of this research, the thesis is aimed at providing a direction for the further development of new EPS and laying a foundation for studying the mechanism of physiological function of Bifidobacterium. The following studies were carried out: 1) A Bifidobacterium strain 22-5 was isolated from a large number of samples and identified as Bifidobacterium stellate by Biolog automatic microbiological identification instrument. The phenol-sulfuric acid method was determined by the recovery test for the determination of this EPS. 2) the culture conditions and medium composition of EPS production by Bifidobacterium stellate 22-5 were optimized. The results showed that the optimum culture conditions were constant temperature anaerobic culture at 25 鈩，

本文編號：1944113