Integrated bioproduction and extraction of 3-methylcatechol

Pseudomonas putida MC2 is a solvent-tolerant strain that accumulates 3-methylcatechol. In aqueous media, 10 mM of 3-methylcatechol was produced and production was limited by 3-methylcatechol toxicity to the biocatalyst. Production levels increased by introduction of a second, organic phase that provides the substrate toluene and extracts the product from the culture medium. Octanol was shown to be an appropriate second phase with respect to tolerance of the strain for this solvent and with respect to partitioning of both substrate and product. Per unit of overall reactor volume (octanol and water), best results were obtained with 50% (v/v) of octanol: an overall 3-methylcatechol concentration of 25 mM was reached with 96% of the product present in the octanol phase. These product concentrations are much higher than in aqueous media without organic solvent, indicating that biocatalysis in an organic/aqueous two-phase system is an improved set-up for high production levels of 3-methylcatechol.