Identification of 3-Phenyllactic Acid As a Possible Antibacterial Substance Producedby Enterococcus faecalis TH10

摘要

Enterococcus faecalis TH10 is a lactic acid bacterial strain isolated from the Malaysian traditional fermented food, "tempeh", and has antibacterial activity against various pathogens. To identify the antibacterial substance, the butanol extract of the culture supernatant of E. faecalis TH10 was fractionated by HPLC equipped with a reversed-phase partition column, and the elutes were subjected to antibacterial assay. As the activity was observed in a fraction eluted by ca 80% methanol, the fraction was analyzed by gas chromatography/mass spectrometry and 3-phenyllactic acid was identified as the major compound. Fractionation with an optical isomer separation column showed that the preparation contained D- and L-forms of 3-phenyllactic acid at a ratio of 2:1. Authentic 3-phenyllactic acid showed antibacterial activity against various bacteria such as Staphylococcus aureus and Escherichia coll. These results suggest the possibility that 3-phenyllactic acid is a biopreservative.