Researchers Analyze High-Lignin Feedstocks for Potential Applications in Biofuel and Bio-based Chemicals Production

In the biofuel-ethanol production process from lignocellulosic biomass, the focus is usually the carbohydrate fractions (cellulose and hemicellulose) of the biomass, which are extracted for further processing into ethanol. The lignin residue is often separated and regarded as a waste stream, because "structural diversity and heterogeneity" of this material can make further processing to biofuels or value-added-chemicals a challenge. In anticipation of future technological developments for the processing of lignin into value-added products, a collaborative team of research scientists from the University of Kentucky and the University of Massachusetts used thermal deconstruction to "identify and examine feedstocks that possess naturally high lignin contents.

They performed preliminary experiments to "examine the pyrolytic characteristics of the various feedstocks and to estimate the potential" of these materials for the production of biofuels, bioelectricity or specialty chemicals. "Drupe endocarp"biomass (seen as agricultural wastes from horticultural crops) was identified as a feedstock containing high levels of lignin. The researchers characterized the lignin-derived deconstruction products of endocarp biomass (by pyrolysis coupled to gas chromatography-mass spectrometry) and compared them to switchgrass (a potential feedstock for biofuels production). They found that high-lignin endocarp biomass yielded higher levels of lignin-based pyrolytic products compared to switchgrass; (switchgrass had higher levels of acetic acid and furfural). The results indicated that high-lignin endocarp biomass can be a "source of renewable production of value-added chemicals, like phenol, 2-methoxyphenol, 2-methyl phenol, 2-methoxy-4-methylphenol,and 4-methoxy-2-ethylphenol". The full study is published in the open-access journal, Biotechnology for Biofuels.