Transcription factor-based biosensors for detecting dicarboxylic acids

A method of detecting a dicarboxylic acid, the method comprising

• providing a recombinant host cell that comprises:
• a heterologous nucleic acid that encodes a transcription factor that comprises a binding region that can bind to and activate a promoter and a protein moiety that binds a dicarboxylic acid;
• and
• a heterologous nucleic acid that comprises a reporter gene operably linked to the promoter that is activated by the transcription factor;
• culturing the host cell under conditions in which the transcription factor is produced, wherein the dicarboxylic acid, when present, binds to the protein, thereby activating the transcription factor to activate transcription of the reporter gene;
• and
• detecting expression of the reporter gene.