Biological conversion of cyclic ketones from catalytic fast pyrolysis with Pseudomonas putida KT2440

Catalytic fast pyrolysis (CFP) of lignocellulosic biomass is under intense investigation to produce sustainable biofuels. CFP produces a heterogenous bio-oil fraction rich in oxygenated species, including cyclic ketones. While the high oxygen content of CFP bio-oil renders it unsuitable for direct use as transportation fuel replacement or blendstock, many oxygenates can be separated and upgraded to value-added chemicals to offset biofuels' production cost. In this work, we isolated fractions enriched in cyclic ketones from ex situ CFP bio-oil and metabolically engineered the robust soil bacterium Pseudomonas putida KT2440 to upgrade these ketones to hydroxy and dicarboxylic acids, which have a broad set of industrial applications, especially for use in polymers. P. putida was adapted to higher concentrations of the cyclic ketone substrate, 2-cyclopenten-1-one, to further improve the conversion process. Overall, this work demonstrates the valorization of an important class of compounds found in CFP bio-oil, further expanding the possibilities of producing valuable bioproducts in CFP processes, especially from substrates that are disadvantaged for biofuels production.