Title: HSQC spectra of lignin isolated from poplar roots

Abstract

Here we present a curated dataset of two-dimensional heteronuclear single quantum coherence (HSQC) nuclear magnetic resonance (NMR) spectra of lignin isolated from roots of a greenhouse grown natural population of an energy crop poplar (Populus trichocarpa). Dormant cuttings of field-grown poplar were grown in 6-liter pots in a peat-based media containing bark, perlite, vermiculite, dolomite lime and a wetting agent in an environmentally controlled greenhouse. Temperatures were between 21 and 23 °C, with supplemental lighting to support a 16-h day length using 1000-watt high-pressure sodium lights in greenhouse. Once established, all plants were cut-back, allowed to regrow and harvested at the same time following an eight-month long growth period. Plants were harvested and the belowground roots were washed off soils, blotted, dried in an oven at 70 °C for 3 days, and Wiley milled (mesh size 20). The roots were Soxhlet-extracted with toluene/ethanol for 24 h to remove extractives. The extracted roots were ball-milled in a Retsch PM100 planetary ball mill using a porcelain jar with ceramic balls at 600 rpm for 2 h (in 5 min on and 5 min off cycles to avoid excessive sample heating). The ball-milled materials were then subjected to enzymatic hydrolysis for 48 hmore » followed by centrifugation and washing with deionized water. The solid residue was extracted twice with 96% (v/v) 1,4-dioxane/water mixture at room temperature overnight. The extracts were combined, rotary evaporated, and freeze-dried to recover lignin. The dry lignin samples were dissolved in deuterated dimethyl sulfoxide (d6) and transferred into a 5 mm tube. 13C–1H HSQC experiments were performed in a Bruker Avance III HD 500 MHz NMR spectrometer operating at a frequency of 125.12 MHz for the 13C nucleus using a standard Bruker pulse sequence on a Prodigy platform cryoprobe. The NMR spectra were acquired under the following acquisition conditions: 220 ppm spectral width in F1 (13C) dimension with 256 data points and 12 ppm spectral width in F2 (1H) dimension with 1024 data points, a 90° pulse, a one bond C–H coupling constant of 145 Hz, a 1.0 s pulse delay, and 64 scans. Spectra were processed using the Bruker TopSpin software. Additional meta data is embedded in the raw spectra figures.« less

Authors:

Zhang, Junhua; Pu, Yunqiao; Kalluri, Udaya; Ragauskas, Art

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+ Show Author Affiliations

1. Department of Chemical and Biomolecular Engineering, University of Tennessee Knoxville, Knoxville, TN, USA
2. Joint Institute for Biological Sciences, Bioscience Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, USA
3. Department of Chemical and Biomolecular Engineering, University of Tennessee Knoxville, Knoxville, TN, USA Joint Institute for Biological Sciences, Bioscience Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA Center for Bioenergy Innovation, Oak Ridge National Laboratory, Oak Ridge, TN, USA

Publication Date:

Fri Sep 20 00:00:00 EDT 2024

DOE Contract Number:  

AC05-00OR22725

Research Org.:

Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Biological and Environmental Research (BER). Earth & Environmental Systems Science (EESS)

Subject:

HSQC, lignin, poplar, roots, CBI

OSTI Identifier:

2447143

DOI:

https://doi.org/10.25983/2447143