Nanoscale interactions of polyethylene glycol with thermo-mechanically pre-treated Pinus radiata biofuel substrate

• Published in: Biotechnology and bioengineering Vol. 111; no. 4; pp. 719 - 725
• Main Authors: Donaldson, Lloyd A., Newman, Roger H., Vaidya, Alankar
• Format: Journal Article
• Language: English
• Published: United States Blackwell Publishing Ltd 01.04.2014; Wiley Subscription Services, Inc
• Subjects: Bioengineering; biofuel substrate; Biofuels; Cellulase; Cellulose; Enzymes; Fluorescence; fluorescence microscopy; Fluorescence Resonance Energy Transfer; Fragments; FRET; Fretting; Fuels; Lignin - chemistry; Lignin - ultrastructure; Lignocellulose; Microscopy, Fluorescence; Nanostructure; Nanostructures - chemistry; Pinus - chemistry; Pinus radiata; Polyethylene glycol; Polyethylene Glycols - chemistry; polyethyleneglycol; radiata pine; Spectrum analysis; radiata pine; biofuel substrate; polyethyleneglycol; cellulose; cellulase; FRET; fluorescence microscopy
• ISSN: 0006-3592; 1097-0290
• DOI: 10.1002/bit.25138

ABSTRACT Non‐productive adsorption of cellulose degrading enzymes on lignin is a likely reason for reduced rate and extent of enzymatic conversion of lignocellulosic substrate to sugars. Additives such as polyethyleneglycol (PEG) may act as blocking agents in this non‐productive interaction. However, the exact molecular level interactions of PEG with lignin in pre‐treated lignocellulosic substrates are not known. We have used confocal fluorescence microscopy combined with Förster resonance energy transfer (FRET) to reveal molecular level interactions between lignin present in thermo‐mechanically pre‐treated Pinus radiata substrate, and fluorescently labeled PEG. It is demonstrated that PEG interaction with lignin is mainly associated with particles derived from secondary walls, with little or no penetration into fragments derived from the middle lamella. This nanoscale information on the PEG–substrate interaction will assist in rationalizing pre‐treatment methods to reduce the recalcitrance of softwood biofuel substrates. Biotechnol. Biotechnol. Bioeng. 2014;111: 719–725. © 2013 Wiley Periodicals, Inc. PEG is a useful additive to enzymatic saccharification of pre‐treated softwood biomass which improves glucose yield by reducing non‐specific binding of enzyme to lignin. The authors have used confocal fluorescence microscopy combined with Förster resonance energy transfer (FRET) to reveal molecular level interactions between lignin present in thermo‐mechanically pre‐treated Pinus radiata substrate, and fluorescently labeled PEG.