Methyl ketone production by P. putida with A. thaliana and switchgrass hydrolysates obtained by dilute acid pretreatment led to the identification of plant-derived amino acids, rather than mono-aromatics, as key stimulative components of these hydrolysates. Shotgun proteomics indicated that the amino acids had a specific inductive effect on proteins involved in fatty acid biosynthesis, leading to a 9-fold increase in methyl ketone titer when amending glucose-containing minimal medium with a defined set of amino acids.