The physiobiochemical characteristics of a thermotolerant bacterium strain ZY-3 and characteristics of biosurfactant produced by the strain were studied.The impact of different carbon sources on cell growth and bio-surfactant production of strain ZY-3 was also studied by measuring the cell density and surface tension and emulsification activity in the fermentation broth.The bio-surfactant produced was initially isolated and analyzed accordingly.The strain ZY-3 was primarily identified as the genus Bacillus,it had the features of producing acid and reduce nitrates,but not produce H2S.When strain ZY-3 was fermented in a medium with starting pH at 6.0 and starch as carbon source,more and stable bio-suffactants were produced.When the media for seed and fermentation contained starch,the cell grew better,and the produced surfactant reduced surface tension and stronger emulsificatiou,the produced bio-surfactant could reduced the surface tension of fermentatiun broth from 72.1 mN/m to 53.1 mN/m,and emulsification activity increased from 0 to 24％.It was judged initially that the pruduct was glycolipid anion surfactant.%研究了耐高温生物表面活性剂产生菌ZY-3的生理生化特性,并通过测定发酵液的菌体密度、表面张力和乳化活性等指标,研究不同碳源和初始pH对菌株ZY-3生长和产生物表面活性剂的影响,同时对其所产生物表面活性剂进行了初步分离和性质分析.菌株ZY-3被初步鉴定为芽胞杆菌属(Bacillus),具有产酸、不产H2S、还原硝酸盐等特性.在以淀粉为碳源、初始pH 6.0的培养基中发酵,产生物表面活性剂多且稳定;在种子培养基和发酵培养基中都有淀粉的条件下,菌体生长较多,降低表面张力和乳化的作用均较强,所产生物表面活性剂可以使发酵液的表面张力从72.1 mN/m降到53.1 mN/m,乳化活性从0升高到24％.初步判断产物为糖脂类阴离子表面活性剂.
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