TY - JOUR
T1 - Two-Dimensional 1H-Nuclear Magnetic Resonance Relaxometry for Understanding Biomass Recalcitrance
AU - Jeoh, Tina
AU - Karuna, Nardrapee
AU - Weiss, Noah Daniel
AU - Thygesen, Lisbeth Garbrecht
PY - 2017/10/2
Y1 - 2017/10/2
N2 - Low-field nuclear magnetic resonance (LFNMR) relaxometry examines the influence of the local environments within porous materials on the responses of the water-associated 1H to magnetic fields, yielding information on the chemical and physical surroundings of the water. 1D NMR relaxometry has been used to examine the relationship between water constraint within lignocellulosic biomass microstructure and its enzymatic digestibility; however, the effect of physical confinement and magnetic dephasing by the local chemistry could not be decoupled. This limitation is overcome by two-dimensional T1T2 1H NMR relaxometry, where simultaneously probing the spin-lattice and spin-spin relaxation times of water 1H resolves physical and chemical contributions to relaxation times of unique water environments within the sample. 2D T1T2 relaxation revealed four water environments in Norway spruce assigned to lumen and cell wall water based on water mobility in the pools. Sulfur dioxide (SO2) pretreatment of the spruce eliminated the cell wall water environments, while increasing the mobility of water in the lumens. Subsequent dewatering of pretreated spruce to high dry matter content in the samples significantly decreased water mobility in the lumens without changing the local chemical composition. For the first time, the use of 2D T1T2 relaxation revealed that osmotic pressure exerted by solute (glucose or bovine serum albumin (BSA)) uptake into the microstructure of lignocellulosic biomass expands the volume of the confined spaces such as the cell lumens. The uptake of BSA was associated with increased water retention and enzymatic digestibility of SO2 pretreated spruce. Overall, 2D T1T2 relaxation results suggest a relationship where increasing water mobility in the biomass microstructure reduces its recalcitrance.
AB - Low-field nuclear magnetic resonance (LFNMR) relaxometry examines the influence of the local environments within porous materials on the responses of the water-associated 1H to magnetic fields, yielding information on the chemical and physical surroundings of the water. 1D NMR relaxometry has been used to examine the relationship between water constraint within lignocellulosic biomass microstructure and its enzymatic digestibility; however, the effect of physical confinement and magnetic dephasing by the local chemistry could not be decoupled. This limitation is overcome by two-dimensional T1T2 1H NMR relaxometry, where simultaneously probing the spin-lattice and spin-spin relaxation times of water 1H resolves physical and chemical contributions to relaxation times of unique water environments within the sample. 2D T1T2 relaxation revealed four water environments in Norway spruce assigned to lumen and cell wall water based on water mobility in the pools. Sulfur dioxide (SO2) pretreatment of the spruce eliminated the cell wall water environments, while increasing the mobility of water in the lumens. Subsequent dewatering of pretreated spruce to high dry matter content in the samples significantly decreased water mobility in the lumens without changing the local chemical composition. For the first time, the use of 2D T1T2 relaxation revealed that osmotic pressure exerted by solute (glucose or bovine serum albumin (BSA)) uptake into the microstructure of lignocellulosic biomass expands the volume of the confined spaces such as the cell lumens. The uptake of BSA was associated with increased water retention and enzymatic digestibility of SO2 pretreated spruce. Overall, 2D T1T2 relaxation results suggest a relationship where increasing water mobility in the biomass microstructure reduces its recalcitrance.
U2 - 10.1021/acssuschemeng.7b01588
DO - 10.1021/acssuschemeng.7b01588
M3 - Journal article
SN - 2168-0485
VL - 2017
SP - 8785
EP - 8795
JO - A C S Sustainable Chemistry & Engineering
JF - A C S Sustainable Chemistry & Engineering
IS - 5
ER -