【摘要】 目的:获得一株对口腔变形链球菌具有较强抑制作用的菌株,并对其发酵滤液的抑菌活性进行考察。方法:采用体外筛选法,从土壤中筛选出3株对变形链球菌具有抑制作用的菌株,对它们的性质进行考察。结果:初步鉴定它们均为地衣芽孢杆菌,其中1#菌对变形链球菌的抑制作用最强,在30℃,pH7.0,150r/min的条件下,恒温振荡培养24h,测其发酵滤液对变形链球菌的抑菌效价为1500IU/ml。该发酵滤液具有较强的热稳定性,37℃放置1h,活性下降了35%;60℃放置30min,活性下降了47%,放置1h,活性下降了50%;100℃放置1h,活性仍能保持39%;121℃下放置1h,基本无活性。该发酵滤液抑菌作用的最适pH值为7.0,在pH3.0时能保持70%的活性,在pH11.0时,仍能维持65%的活性。结论:1#菌株发酵滤液对口腔变形菌的抑制作用最强,稳定性最大,是一株很有应用前景的菌株。更多还原

【Abstract】 Objective: To obtain a strain which has stronger antagonistic effect against Streptococcus mutans(S. mutans), and then to study the antagonistic effect of the fermentation filtrate of the strains. Method:Surface soil samples were harvested and used in an in vitro bacteria culture system for screening of antagonistic strains against Streptococcus mutans. Ferment filtrate of the strains was respectively prepared and the antagonism of the filtrate against S. mutans was examined.Result:A strain with strong restrain effect on Streptococcus mutans was found and was identified to be Bacillus licheniformis. The strain was named strain 1#. At pH 7.0, 150 r/min and constant temperature of 30 ℃ cultivated for 24 hours,the antagonistic energy of ferment filtrate was 1 500 IU/ml,the ferment filtrate showed strong heat stability, at 37 ℃ for 1 hour, the activity decreased by 35%; at 60 ℃ for 30 min, by 47%, for 1 h, by 50%, at 100 ℃,the activity maintained 39%.The optimum pH for the activity of the ferment filtrate was 7.0, at pH 3.0, the activity kept 70% and at pH 11.0, 65%.Conclusion:The fermentation filtrate of strain 1# of Bacillus licheniformis is antagonistic against S. mutans.更多还原