Application of Transcription Factor-based 3-Hydroxypropionic Acid Biosensor

Application of the recently developed wholecell 3-HP biosensor, which detects 3-hydroxypropionic acid (3-HP) and expresses fluorescence as an output signal in response to the 3-HP concentration, was studied in three areas of enzyme and metabolic engineering. First, a sensor was applied to identify active 3-hydroxyaldehyde dehydrogenase (ALDH), a key enzyme in the 3-HP production pathway. Second, with the aid of helper enzymes that catalyze the conversion of 1,3-propanediol (1,3-PDO) to 3-HP, a 3-HP biosensor was converted into a 1,3-PDO biosensor. Third, a 3-HP biosensor, with proper modifications in expression module of the output signal and the use of pH-tolerant red fluorescent protein (RFP), was shown to monitor the rate of 3-HP production under process conditions in which one or more interfering compounds are present in the culture medium and/or the medium pH decreases. This study demonstrates that 3-HP biosensors can be widely used in enzyme and metabolic engineering applications for 3-HP production.