Moe, W.M., S.J. Reynolds, M.A. Griffin, and J.B. McReynolds.
Environmental Science & Technology 52(16):9311-9319(2018)

At a contaminated site located near Baton Rouge, Louisiana, a fermentable substrate (agricultural feed grade cane molasses) was injected into the subsurface to provide electron donor for reductive dechlorination of chlorinated solvent contamination in the groundwater. Subsequently, toluene was transiently observed in the groundwater at concentrations sometimes far exceeding the U.S. drinking water MCL of 1 mg/L. Investigation of site data suggested that the indigenous microorganisms were able to produce toluene by conversion of phenylacetic acid, phenylalanine, phenyllactate, and phenylpyruvate. When grown in defined medium with phenylacetic acid at concentrations ≤350 mg/L, the molar ratio between toluene accumulated and phenylacetic acid supplied was highly correlated with a toluene yield exceeding 0.9:1. Experiments conducted using ¹³C-labeled compounds (phenylacetic acid-2-¹³C and l-phenylalanine-3-¹³C) produced toluene-alpha-¹³C, confirming that toluene was synthesized from these precursors by two independently developed enrichment cultures. See more on this study in M.A. Griffin's thesis at https://digitalcommons.lsu.edu/gradschool_theses/4369/.