Synthesis of a compound with folic acid activity by Lactobacillus arabinosus 17-5

Abstract

A compound with folic acid activity is synthesized by growing as well as respiring cells of Lactobacillus arabinosus in the presence of p-aminobenzoic acid. The essentiality of glutamic acid is seen in studies with respiring cells. The free folic acid activity elaborated by Lactobacillus arabinosus reaches its maximum in about 48 hrs. and is present mainly in the culture filtrate. Additions of Tween 80, or biotin and of xanthine show marked stimulation of the synthesis of folic acid activity. With the organisms Streptococcus faecalis R and Lactobacillus casei, requiring exogenous folic acid for growth, it is seen that the entire folic acid activity resides in the cells and as citrovorum factor. Sulphanilamide inhibits the synthesis of folic acid activity by Lactobacillus arabinosus.