本研究以HPLC法分析八株乳酸菌包括雙歧桿菌Bifidobacterium longum B6和15708、嗜酸乳桿菌Lactobacillus acidophilus N-1和4356、保加利亞桿菌Lactobacillusbulgaricus 448和449及嗜熱乳酸鏈球菌Streptococcus thermophilus MC和573合成葉酸之能力。由研究結果發現，在乳酸菌發酵期間以發酵6hr之葉酸生成量最大。而在測試的菌種中，雙歧桿菌顯示有最高的葉酸生成能力，B.longum B6和15708在37℃經發酵6hr後葉酸分別增加了3.5倍和2.4倍，而且五甲基四氫葉酸為主要的葉酸衍生物。

　　　　　Eight strains of lactic acid bacteria, including Bifidobacterium longumB6 and 15708, Lactobacillus acidophilus N-l and 4356, Lactobacillus bulgaricus448 and 449, and Streptococcus thermophilus MC and 573 were investigated fortheir folate synthesizing ability by applying the high-performance liquidchromatographic method. The results showed that lactic acid bacteria synthesizedmaximum levels of folate in six hours in fermented milk. B. longum B6 demonstratedthe highest folate synthesizing ability, and B. longum 15708 also producedfolate satisfactorily. These two strains increased folate 3.5 and 2.4 fold,respectively, after 6h fermentation at 37℃. 5-Methyltetrahydrofolate was themain derivative of folate found in fermented milk.