A novel solid-liquid two-phase partitioning Bioreactor for the enhanced bioproduction of 3-methylcatechol

The bioproduction of 3-methylcatechol from toluene via Pseudomonas putida MC2 was performed in a solid-liquid two-phase partitioning bioreactor with the intent of increasing yield and productivity over a single-phase system. The solid phase consisted of HYTREL TM, a thermoplastic polymer that was shown to possess superior affinity for the inhibitory 3-methylcatechol compared to other candidate polymers as well as a number of immiscible organic solvents. Operation of a solid-liquid biotransformation utilizing a 10% (w/w) solid (polymer beads) to liquid phase ratio resulted in the bioproduction of 3-methylcatechol at a rate of 350 mg/L-h, which compares favorably to the single phase productivity of 128 mg/L-h.. HYTREL (TM) polymer beads were also reconstituted into polymer sheets, which were placed around the interior circumference of the bioreactor and successfully removed 3-methylcatechol from solution resulting in a rate of 3-methylcatechol production of 343 mg/L-h. Finally, a continuous biotransformation was performed in which culture medium was circulated upwards through T an external extraction column containing HYTREL (TM) beads. The design maintained sub lethal concentrations of 3-methylcatechol within the bioreactor by absorbing produced 3-methylcatechol into the polymer beads. As 3-methylcatechol concentrations in the aqueous phase approached 500 mg/L the extraction column was replaced (twice) with a fresh column and the process was continued representing a simple and effective approach for the continuous bioproduction of 3-methylcatechol. Recovery of 3-methylcatechol from HYTREL TM was also achieved by bead desorption into methanol.