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

Abstract

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.