Biosynthesis and Utilization of Folic Acid and Vitamin B12 by Lactic Cultures in Skim Milk

Abstract

Fermentation of skim milk by Streptococcus thermophilus and Lactobacillus acidophilus increased the folate concentration by more than 200%. The increase was dependent on time of incubation with the maximums between 8-24 h. L. bulgaricus reduced folic acid to negligible within a few hours. Vitamin B12 content did not increase, regardless of culture. These results and those of others suggest that contradictions of biosynthesis of folic acid and B12 by lactic cultures may have been from several factors, such as species and strain of culture and incubation time. Precursors of folate, p-aminobenzoic acid and GTP, did not increase folate when added to the skim milk prior to fermentation by the lactic cultures.