Researchers at Iowa State University explored the separate recovery of sugars and phenolic oligomers produced during fast pyrolysis with the effective removal of contaminants from the separated pyrolytic sugars to produce a substrate suitable for fermentation without hydrolysis.
The results suggest that the sugars recovered are promising alternatives for fermentation to ethanol, whereas the phenolic oligomers show potential for the production of aromatic chemicals, resins, binders, coatings, adhesives, carbon fibers, and asphalt. A paper on the work is published in the journal ChemSusChem.
The first two stages from a unique recovery system capture “heavy ends”, mostly water-soluble sugars and water-insoluble phenolic oligomers. The differences in water solubility can be exploited to recover a sugar-rich aqueous phase and a phenolic-rich raffinate.
More than 93 wt % of the sugars is removed in two water washes. These sugars contain contaminants such as low-molecular-weight acids, furans, and phenols that could inhibit successful fermentation. Detoxification methods were used to remove these contaminants from pyrolytic sugars.
The optimal candidate is NaOH overliming, which results in maximum growth measurements with the use of ethanol-producing Escherichia coli.
Rover, M. R., Johnston, P. A., Jin, T., Smith, R. G., Brown, R. C. and Jarboe, L. (2014) “Production of Clean Pyrolytic Sugars for Fermentation.” ChemSusChem doi: 10.1002/cssc.201301259