Bioupgrading of the aqueous phase of pyrolysis oil from lignocellulosic biomass: a platform for renewable chemicals and fuels from the whole fraction of biomass

Abstract

Pyrolysis, a thermal decomposition without oxygen, is a promising technology for transportable liquids from whole fractions of lignocellulosic biomass. However, due to the hydrophilic products of pyrolysis, the liquid oils have undesirable physicochemical characteristics, thus requiring an additional upgrading process. Biological upgrading methods could address the drawbacks of pyrolysis by utilizing various hydrophilic compounds as carbon sources under mild conditions with low carbon footprints. Versatile chemicals, such as lipids, ethanol, and organic acids, could be produced through microbial assimilation of anhydrous sugars, organic acids, aldehydes, and phenolics in the hydrophilic fractions. The presence of various toxic compounds and the complex composition of the aqueous phase are the main challenges. In this review, the potential of bioconversion routes for upgrading the aqueous phase of pyrolysis oil is investigated with critical challenges and perspectives. Graphical Abstract

Two-stage conversion of syngas and pyrolysis aqueous condensate into L-malate

“…Techno-economical assessments have highlighted the potential of integrating thermochemical and biological processes to improve carbon and energy recovery and to minimize the environmental impact of agricultural wastes [7][8][9][10][11]. In recent studies focusing on the biochemical conversion of some PAC components, researchers combined physiochemical pre-treatments with axenic fermentations to produce a wide range of products [12][13][14][15][16]. Others have utilized the diversity and functional redundancy of the microbial network in the anaerobic digestion process to convert PAC components into biogas.…”