http://synbioproject.tech/cpi/applications/mandelic-acid/
Mandelic acid, is phenylglycollic acid, an alpha-hydroxy acid (AHA) named after the German (almond) and derived from the hydrolysis of an extract of bitter almonds has been studied extensively for its anti-aging and antimicrobial effect. Mandelic Acid has a hydroxyl group on the carbon atom next to the acid group. It is an 8-carbon alpha-hydroxy acid [HOCH (C6H5) COOH]. Source
Customized E. Coli (and some other microorganisms) could affect the necessary conversion processes under the right circumstances.