In situ phenol removal from fed-batch fermentations of solvent tolerant Pseudomonas putida S12 by pertraction

Abstract

In situ phenol pertraction with 1-octanol has been experimentally studied to improve the production of the model component phenol by a recombinant strain of Pseudomonas putida S12. When the phenol concentration in the reactor reaches 2mM, the cells in fermentations without phenol removal are inhibited in growth and phenol production. Growth and phenol production stop after approximately 80h at a phenol concentration in the reactor of 3.8mM. When phenol is removed from the fermentation broth by pertraction, a lower maximum aqueous phenol concentration of 2.6mM is achieved, while the total phenol production increases to 132%, as compared to the fermentation without pertraction. There are indications that the volumetric productivity (mmolL−1h−1) increases slightly in the fermentations with in situ pertraction compared to the reference experiments. As expected, the amount of phenol produced per gram biomass (the specific productivity, mmolg−1L−1) remains constant in time for all fermentations. The use of pertraction for in situ phenol removal is compared to in situ second phase extraction, in situ solvent impregnated resins and in-stream pertraction. Although the system shows promising results, further modifications such as using a solvent with a higher partition coefficient can improve the overall performance.