本文選題：雙歧桿菌 + 鑒定��； 參考：《內(nèi)蒙古農(nóng)業(yè)大學(xué)》2012年碩士論文

【摘要】：本研究采用選擇性培養(yǎng)基對河南、四川、西藏、云南、內(nèi)蒙古和新疆等地區(qū)的18份人體糞便樣品中的雙歧桿菌進行了分離純化,并采用16S rRNA基因序列分析法對分離到的29株雙歧桿菌進行了鑒定。以B.animalis subsp.Iactis V9為參照,通過耐酸性、人工消化液和膽鹽耐受試驗,篩選出胃腸道轉(zhuǎn)運過程中耐受性較好的4株雙歧桿菌。并對篩選出的雙歧桿菌進行了脫脂乳發(fā)酵特性和貯藏特性的研究。 試驗結(jié)果表明,從18位中國部分地區(qū)健康人體糞便中分離得到29株雙歧桿菌,經(jīng)16S rRNA基因序列分析法將IMAUFB064、IMAUFB065和IMAUFB091等9株菌鑒定為B. longum,其中河南6株、四川2株和新疆1株；將IMAUFB071、IMAUFB073、 IMAUFB084、IMAUFB090和IMAUFB092等20株菌鑒定為B.pseudocatenulatum,其中四川9株、西藏7株、云南3株和內(nèi)蒙古1株。29株雙歧桿菌中有24株在pH3.0、3.5和4.0的改良MRS培養(yǎng)液中生長良好,初篩出的24株雙歧桿菌分別經(jīng)pH3.0、2.5、2.0人工胃液消化3h后,存活率高于V9(84.97%)的菌株有2株,分別為IMAUFB084(85.98%)和MAUFB073(85.66%),占總菌數(shù)的6.90%,各菌株在不同pH值人工胃液中耐受性有顯著差異(P0.05),隨著pH值的降低,供試菌株對模擬人工胃液的耐受性也隨之降低。4株復(fù)篩出的雙歧桿菌在人工腸液消化8h后,其中MAUFB090的存活率為101.8%,高于V9(97.84%),MAUFB073(97.19%)、IMAUFB084(94.38%)和IMAUFB064(89.93%)都低于V9的存活率。 4株雙歧桿菌均能耐受2.0%膽鹽濃度,但各菌株的延遲時間差異顯著(p0.05),IMAUFB064延遲時間為0.59h,為可耐受膽鹽菌株；IMAUFB084、IMAUFB073和IMAUFB090的延遲時間表明其為輕微耐受膽鹽菌株；參考菌株V9的延遲時間為0.25h,為對膽鹽不敏感菌株,顯而易見,各供試菌株對膽鹽的耐受性均低于V9。 分別以IMAUFB064、IMAUFB073、IMAUFB084、IMAUFB090和V9單菌株發(fā)酵制備酸乳,結(jié)果表明：IMAUFB073到達發(fā)酵終點的時間最短,僅用了18h,發(fā)酵結(jié)束時活菌數(shù)為6.02×108, MAUFB090、V9、IMAUFB084和IMAUFB064到達發(fā)酵終點的時間均為21h,活菌數(shù)分別為5.44×108、5.13×108、3.91×108和3.33×108。貯藏發(fā)酵乳的過程中,14d之后4株供試菌株的pH值下降速度顯著低于V9；21d后V9和MAUFB084的活菌數(shù)不但沒有下降反而分別增加了0.06和0.01個單位(logcfu/g),IMAUFB064的活菌數(shù)也沒有明顯的下降,說明V9、1MAUFB084和IMAUFB064在貯藏過程中的穩(wěn)定性比IMAUFB073和IMAUFB090好,有利于益生菌制品的開發(fā)。
[Abstract]:In this study, a selective medium was used to isolate and purify Bifidobacterium in 18 human feces samples from Henan, Sichuan, Tibet, Yunnan, Inner Mongolia and Xinjiang, and 29 strains of Bifidobacterium were identified by 16S rRNA gene sequence analysis. The acid tolerance of B.animalis subsp.Iactis V9 was used as a reference. 4 strains of bifidobacteria, which were well tolerated during the transport of stomach and intestines, were screened by artificial digestive juice and bile salt tolerance test. The fermentation characteristics and storage characteristics of the screened bifidobacteria were studied.
The results showed that 29 strains of Bifidobacterium were isolated from 18 healthy human feces, and 9 strains of IMAUFB064, IMAUFB065 and IMAUFB091 were identified as B. longum by 16S rRNA gene sequence analysis, including 6 Henan, 2 Sichuan and 1 Xinjiang, 20 strains of IMAUFB071, IMAUFB073, IMAUFB084, IMAUFB090, IMAUFB092 and other strains. The bacteria were identified as B.pseudocatenulatum. Among them, 9 strains of Sichuan, 7 Tibet, 3 Yunnan and 1 strains of Bifidobacterium in Inner Mongolia were grown well in pH3.0,3.5 and 4 modified MRS culture. 24 strains of bifidobacteria were screened by pH3.0,2.5,2.0 artificial gastric juice for 3h, and the survival rate was higher than that of V9 (84.97%), which were IMA, respectively. UFB084 (85.98%) and MAUFB073 (85.66%) accounted for 6.90% of the total number of bacteria. The tolerance of each strain in the artificial gastric juice with different pH values was significantly different (P0.05). With the decrease of pH value, the tolerance of the tested strains to simulated artificial gastric juice also reduced the.4 strain of Bifidobacteria after the digestion of 8h in the artificial intestinal juice, and the survival rate of MAUFB090 was 101.8%, Higher than V9 (97.84%), MAUFB073 (97.19%), IMAUFB084 (94.38%) and IMAUFB064 (89.93%) were all lower than V9 survival rate.
4 strains of bifidobacteria could tolerate 2% bile salt concentration, but the delay time of each strain was significantly different (P0.05), the delay time of IMAUFB064 was 0.59h, and the delay time of IMAUFB084, IMAUFB073 and IMAUFB090 indicated that it was a mild resistant strain of bile salt; the delay time of the reference strain V9 was 0.25h, which was an insensitive strain to the bile salt. Obviously, the tolerance of the tested strains to bile salt was lower than that of V9..
Acid milk was prepared by single strain of IMAUFB064, IMAUFB073, IMAUFB084, IMAUFB090 and V9 respectively. The results showed that the time of IMAUFB073 to reach the end of fermentation was the shortest, only 18h was used, the number of living bacteria was 6.02 x 108 at the end of fermentation, the time of MAUFB090, V9, IMAUFB084 and IMAUFB064 reached the end of fermentation, and the number of living bacteria was 5.44 * * * * In the process of.91 x 108 and 3.33 x 108. storage fermented milk, the decrease rate of the pH value of the 4 strain strains after 14d was significantly lower than that of V9; the living bacteria number of V9 and MAUFB084 after 21d not only did not decrease, but increased 0.06 and 0.01 units respectively (logcfu/g), and the number of IMAUFB064 was not clearly decreased, indicating that V9,1MAUFB084 and IMAUFB064 were stored in storage. The stability of the process is better than that of IMAUFB073 and IMAUFB090, which is beneficial to the development of probiotic products.

【學(xué)位授予單位】：內(nèi)蒙古農(nóng)業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2012
【分類號】：R371

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