乳酸菌素產(chǎn)生菌的篩選及其發(fā)酵產(chǎn)物性質(zhì)的初步研究.pdf

1、乳酸菌素產(chǎn)生菌的篩選及其發(fā)酵產(chǎn)物性質(zhì)的初步研究微生物學(xué)專業(yè)研究生:田宇指導(dǎo)教師:王忠彥副教授摘要以各地采集的包括四川某地使用一百余年的泡菜水作為樣本，采用以1.5mLEp管培養(yǎng)菌液，用紙片法篩選抗生物質(zhì)產(chǎn)生菌的篩選方法進(jìn)行初篩，再以杯碟法進(jìn)行復(fù)篩。采用這一篩選模型，經(jīng)過反復(fù)分離篩選，得到一株對多種革蘭氏陽性和革蘭氏陰性指示菌具有廣譜抑菌活性且對綠膿桿菌具有較強(qiáng)抑菌活力的乳酸菌素產(chǎn)生菌，菌株編號HF08。經(jīng)形態(tài)觀察及生理生化實驗，初步鑒定

2、該菌株為瑞士乳桿菌(Lactobacillushelveticus)通過單因素分析和正交實驗，進(jìn)一步確定該菌株產(chǎn)乳酸菌素的最適發(fā)酵條件:以2%葡萄糖為碳源，1%蛋白陳和。5%酵母膏為氮源，培養(yǎng)基起始pH5.5250mL容量瓶裝量為250mL，種齡72h，接種量1%，37℃靜置培養(yǎng)48h，發(fā)酵產(chǎn)物的抑菌活性可達(dá)141UImL(以硫酸慶大霉素為對照)。對該乳酸菌素生物學(xué)特性進(jìn)行初步研究，發(fā)現(xiàn)用蛋白酶K處理發(fā)酵上清液后，抑菌活性喪失.該乳酸菌

3、素具有較好的熱穩(wěn)定性:顯示抑菌活性的pH值范圍是3.5~5.500.002moULK和Mn“對HF08菌株發(fā)酵產(chǎn)物的抑菌活性有增強(qiáng)作用，F(xiàn)e2、Cu2、Cat對其發(fā)酵產(chǎn)物的抑菌活性有抑制作用，而Na`和Mg2.對其影響不StudyonStrainScreeningandBacteriostasisAvtivityofanovelLactobacillinproducingStrainMajor:microbiologyPostgradu

4、ate.TIANYuTutor:WANGZhongyonABSTRACTAnovellactobacillinproducingstrainwasscreenedandisolatedfrompicklesamples.Akindofnewpreliminaryisolationwayofbacteriumproducingantibioticsubstancewasused:culturingbacteriumbyEptubesand

5、isolationbacteriumbypaperdisktestThestrainwasidentifiedasLactobacillusbelveticusbytestingphysiologicalbiochemicalandmorphologiccharacteristics.WenameitIIF08.Fermentationconditionsforlactobacillinproductionhavebeenestabli

6、shed:2%glucoseascarbonsource1%peptoneand0.5%yeastextractasnitrogensourceinitialpH5.5culturemediumvolumesfor250m1in250mlsteadyshakeseedsagefor72hinocution1%andculturetemperature370Cfor48h.Thebacteriostasisavtivitycanthenr

7、each141UmLTheinhibitoryactivityofthefermentertotallylostaftertreatmentwithproteinaseK.ThiskindoflactobacillinsubstancehasveryhighheatstabilityandactiverangeofpH(3.56.0).Theinhibitoryactivitywasstimulatedby0.002molLK`andM