Mutant libraries 4-hydroxybenzoic acids 1 Acid production 1 Biosensors 1 Directed evolution 1 Error prone PCR 1 Fluorescence activated cell sorting 1 Hydroxy-mandelic acid 1 Hydroxymandelic acid 1 Improved activities 1 Libraries 1 Ligand binding 1 Ligand specificity 1 Ligands 1 Mandelic acid 1 Mutagenesis 1 Organic acids 1 PobR 1 Pobr 1 Point mutations 1 Protein library 1 Protein stability 1 Protein structure prediction 1 Proteins 1 Saturation mutagenesis 1 Screening 1 Single sites 1 Transcription 1 Transcription factors 1