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™, 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™ 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 an external extraction column containing HYTREL™ 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™ was also achieved by bead desorption into methanol. Biotechnol. Bioeng. 2007; 98: 1008–1016. © 2007 Wiley Periodicals, Inc.