中文摘要：

益生菌FGM株发酵黄芪后，产物粗多糖得率显著提高。为进一步提高FGM株发酵黄芪转化多糖的稳定性，本试验将连续传代的FGM株种子液接种黄芪进行液体发酵，采用细菌平板计数法和苯酚-硫酸法分别测定发酵前、后的细菌总数和发酵后黄芪多糖的含量，并对结果进行了统计学分析。结果表明菌种在多次连续传代后会产生菌种退化现象，发酵产物中多糖含量与种子液细菌总数呈极显著相关（P=0．007），其中第4代种子液发酵黄芪转化多糖的性能最高。

英文摘要：

The assay was aimed to further improve the stability of fermentation of Astragalus membranaceus by Streptococcus alactolyticus FGM strain. First,Astragalus membranaceus was inoculated with the successively passaged FGM strain to fermentation, then we measured the viable counts of FGM strain and the yield of Astragalus polysaccharide （APS） by bacteria plate count method and phenol-sulfuric acid method, respectively. Finally, we made a statistical analysis. The results showed that the multiple continuous passage of FGM strain had caused the serious degeneration phenomenon of FGM strain and extremely significantly affected the yield of APS （P= 0. 007）, so the fermentation performance was the strongest after the 4th generation of subculture.