Title: Heteronuclear single quantum coherence (HSQC) NMR spectra of lignin isolated from switchgrass residues after fermentation with milling

Abstract

Here we present a curated dataset of two-dimensional heteronuclear single quantum coherence (HSQC) nuclear magnetic resonance (NMR) spectra of lignin isolated from a herbaceous energy crop (Panicum virgatum L.). The lowland variant “Timber” switchgrass from Ernst seeds was used. The switchgrass was knife milled and passed through a 2 mm sieve prior to consolidated bioprocessing (CBP) process. Switchgrass was suspended in Milli-Q water and autoclaved for 90 min on liquid cycles. The residues after autoclaving were then subjected to CBP using coculture of Clostridium thermocellum (C. thermocellum DSM 1313 (LL1004)) and Thermoanaerobacterium thermosaccarolyticum ( T. thermosaccharolyticum HG-8 ATCC 31960 (LL1244)). Once-fermented and twice-fermented (FF) switchgrass were subjected to ball and disc milling in bioreactors at 55 °C and 60, 48 grams/L solids loadings for primary and secondary fermentation respectively. When fermentations were completed, the residual solids were rinsed with milli-Q water. Lignin was isolated from the pretreated residues after ball-milling in a porcelain jar with ceramic balls via Retsch PM 200 at 600 rpm for 2 h followed by enzymatic hydrolysis in acetate buffer (pH 4.8, 50 °C) for 48 h. The dry lignin samples were dissolved in deuterated dimethyl sulfoxide (d6) and characterized using 13C–1H HSQC in a Brukermore » Avance III HD 500-MHz NMR spectrometer. A standard Bruker pulse sequence (hsqcetgpsisp.2) was used on a Prodigy platform cryoprobe. The spectra were acquired with the following acquisition conditions: 230 ppm spectral width in F1 (13C) dimension with 256 data points and 12 ppm spectral width in F2 (1H) dimension with 2048 data points, a 90° pulse, with a C–H coupling constant of 145 Hz, a 1.0 s pulse delay, and 64 scans. Spectra were processed using the Bruker TopSpin 3.6 software.« less

Authors:

Kousika, Rohit; Pu, Yunqiao; Hoey, Madeline; Holwerda, Evert; Bomble, Yannick; Hengge, Neal; Ragauskas, Art

---

+ Show Author Affiliations

1. Department of Chemical and Biomolecular Engineering, University of Tennessee Knoxville, Knoxville, TN, USA
2. Thayer School of Engineering, Dartmouth College, Hanover, NH,
3. Thayer School of Engineering, Dartmouth College, Hanover, NH Center for Bioenergy Innovation (CBI)
4. Biosciences Center, National Renewable Energy Laboratory, Golden, CO.
5. 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:

Wed Sep 18 04:00:00 UTC 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:

Lignin, HSQC, Switchgrass, CBP , Ball mill, Disc mill. , CBI

OSTI Identifier:

2446777

DOI:

https://doi.org/10.25983/2446777