Identification of Escherichia coli biomarkers responsive to various lignin-hydrolysate compounds

► Identification of the major gene ontologies affected by ferulic acid exposure. ► Strong induction of the MarR regulon and aaeXAB operon by the hydrolysate compounds. ► Selection and verification of five biomarkers genes: aaeA, aaeB, marA, inaA and htpG. ► Evaluation of numerous compounds identified in plant hydrolysates, including furfural. ► Tests with spruce hydrolysate led to a strong induction of the MarR regulon genes.