Umesh P. Agarwal
One Gifford Pinchot Drive
Madison, WI 53726-2398
Current research interests are extended in a number of areas. The focus is on both applied and fundamental investigations. Understanding the roles of lignin and cellulose-crystallinity in the enzyme hydrolysis of wood is an area that will have impact on the biofuel economy. Advances in wood cell wall nanostructure will permit better understanding of the complex ultrastructural interactions incorporating cellulose nanofibril, hemicellulose and lignin. Past and ongoing Raman spectroscopy research at FPL has made it possible to obtain useful information when cellulose and lignin based materials are analyzed. Such analysis can now be carried out both at macro- and micro-levels. For determining the crystallinities of nano-celluloses and other cellulose containing materials, including wood, development of new methods based on Raman spectroscopy is an active area of research. For lignin analysis, a new method based on use of silver metal particles was recently developed that lets trace amounts of lignin to be detected. Development and utilization of Raman spectroscopy for characterization of cellulose nanomaterials and their composites is an area of interest. Lastly, the objective of the Raman database project is to generate information from the lignin models that will help decipher lignin spectrum in a material.
- Understanding roles of lignin and cellulose-crystallinity in enzyme hydrolysis of wood
- Wood cell wall nanostructure
- Advancing Raman spectroscopy for characterzation of nanocelluloses, nanocellulose composites, and woody tissue
- Methods for estimating crystallinity of cellulose containing materials
- Using nano- and micro-particles of silver and other metals in lignin analysis
- Raman database of lignin model compounds and spectral interpretation
Why This Research is Important
Understanding roles of lignin and cellulose-crystallinity in enzyme hydrolysis of wood: For the conversion of wood to ethanol, the enzymatic hydrolysis of cellulose via glucose and fermentation is one of the most practical approaches and therefore, is an important area of research. Cellulose and lignin are essential components of wood but due to the inaccessibility of cellulose to enzymes within the complex cell wall matrix cellulose is not easily hydrolyzed. In addition to accessibility to cellulose its crystallinity remains an issue. Therefore, effects of cellulose crystallinity and lignin removal are two factors important that need to be the focus of investigation.Wood cell wall nanostructure: The problem of composition and architecture of wood cell wall is an important research topic and efforts over the years have revealed that the ultrastructure is complex and remains inadequately understood. The research objectives of the project “understanding the nanostructure of the wood cell wall” consist of (1) characterizing, non-invasively, plant cell wall in a number of tissue types, at the molecular level using Raman mapping and (2) understanding distribution and organization of lignin and cellulose in various morphological regions of woody tissues. The findings are expected to have important implications for several areas of research. A few examples of where such information may be of significance are, “structure-property relationships of cell-wall and wood-fiber”, “lignin biosynthesis and topochemistry”, and “deconstruction of plant cell walls” (where the recalcitrance of plant biomass to degradation is a function of how polymers crosslink and aggregate within walls). Advancing Raman spectroscopy for characterizing, nanocelluloses, nanocellulose-polymer composites, and woody tissue: Cellulose nanocrystals (CNCs) and cellulose nanofibers (CNFs) are important new materials in field of cellulose science and technology. These materials have generated remarkable excitement in the scientific community. The materials have unique physicochemical properties and have been used as reinforcing components in nanocomposites. Additional benefits arise from the fact that they are derived from the biomass that is both renewable and sustainable. Methods for accurately estimating crystallinity of nanocelluloses and cellulose containing materials: Crystallinity has an important effect on the physical, mechanical, and chemical properties of cellulose based materials. Raman spectroscopy has become an important analytical technique for nondestructive, qualitative, and quantitative analysis of cellulose-containing materials. Recent research performed in the scientist’s group has shown it is possible to develop Raman spectroscopy based methods to accurately estimate crystallinity of plant based biomaterials. However, further research is needed to fully develop this approach and address a number of remaining issues. Using nano- and micro-particles of silver and other metals in lignin analysis: Because of the heterogeneous nature of lignin structure, the structures of lignins have proven to be difficult to study even in their native states. Lack of detailed information on lignin structures has hindered progress in a number of science and technology fields. Although a number of Raman techniques have been used to study lignin, the focus under this project is to develop Surface-enhanced Raman scattering (SERS) for this purpose. Raman database of lignin model compounds and spectral interpretation: The objective is to develop a Raman database of lignin model compounds which will be ideal for interpretation and classification of spectra of lignins and/or lignocellulosics. Such information is deemed essential for analyzing the spectra of woods and other lignin containing materials.
Featured Publications & Products
- Agarwal, Umesh P.; Reiner, Richard S.; Ralph, Sally A. 2010. Cellulose I crystallinity determination using FT-Raman spectroscopy : univariate and multivariate methods.
- Agarwal, Umesh P. 2006. Raman imaging to investigate ultrastructure and composition of plant cell walls : distribution of lignin and cellulose in black spruce wood (Picea mariana).
- Agarwal, Umesh P.; Sabo, Ronald; Reiner, Richard S.; Clemons, Craig M.; Rudie, Alan W. 2012. Spatially Resolved Characterization of Cellulose Nanocrystal-Polypropylene Composite by Confocal Raman Microscopy.
- Agarwal, Umesh P.; Atalla, Rajai. 2010. Vibrational spectroscopy.
- Agarwal, Umesh P.; Reiner, Richard S.; Filpponen, Hari; Isogai, Akira; Argyropoulos, Dimitris S. 2010. Crystallinities of nanocrystalline and nanofibrillated celluloses by FT-Raman spectroscopy.
Publications & Products
- Agarwal, Umesh P. 2014. 1064nm FT-Raman spectroscopy for investigations of plant cell walls and other biomass materials.
- Agarwal, Umesh P.; Ralph, Sally A.; Reiner, Richard S.; Moore, Roderquita K.; Baez, Carlos. 2014. Impacts of fiber orientation and milling on observed crystallinity in jack pine.
- Agarwal, Umesh; Ralph, Sally. 2014. On the conflicting findings of Role of Cellulose-Crystallinity in Enzume Hydrolysis of Biomass.
- Qing, Yan; Sabo, Ronald; Zhu, J.Y.; Agarwal, Umesh; Cai, Zhiyong; Wu, Yiqiang. 2013. A comparative study of cellulose nanofibrils disintegrated via multiple processing approaches.
- Agarwal, Umesh P.; Reiner, Richard S.; Ralph, Sally A. 2013. Chapter 1.1 Crystallinity of Nanocellulose Materials by Near-IR FT-Raman Spectroscopy.
- Agarwal, Umesh; Sabo, Ronald; Reiner, Richard; Clemons, Craig; Rudie, Alan. 2013. Chapter 1.4 Spatially Resolved Charaterization of CNC-Polypropylene Composite by Confocal Raman Microscopy.
- Agarwal, Umesh P.; Zhu, J.Y.; Ralph, Sally A. 2013. Enzymatic hydrolysis of loblolly pine: effects of cellulose crystallinity and delignification.
- Agarwal, Umesh P.; Reiner, Richard R.; Ralph, Sally A. 2013. Estimation of Cellulose Crystallinity of Lignocelluloses Using Near-IR FT-Raman Spectroscopy and Comparison of the Raman and Segal-WAXS Methods.
- Mun, Sung Phil; Cai, Zhiyong; Watanabe, Fumiya; Agarwal, Umesh P.; Zhang, Jilei. 2012. Thermal Conversion of Pine Wood Char to Carbon Nanomaterials in the Presence of Iron Nanoparticles.
- Agarwal, Umesh P.; Reiner, Richard R.; Ralph, Sally A. 2011. Cellulose crystallinity of woods, wood pulps, and agricultural fibers by FT-Raman spectroscopy.
- Agarwal, Umesh P.; Zhu, J.Y.; Ralph, Sally A. 2011. Enzymatic hydrolysis of biomass : effects of crystallinity, particle size, and lignin removal.
- Agarwal, Umesh P.; McSweeny, James D.; Ralph, Sally A. 2011. FT-Raman investigation of milled-wood lignins : softwood, hardwood, and chemically modified black spruce lignins.
- Agarwal, Umesh P. 2011. Lignin quantitation by FT-Raman spectroscopy.
- Chundawat, Shishir P. S.; Donohoe, Bryon S.; Sousa, Leonardo da Costa; Elder, Thomas; Agarwal, Umesh P.; Lu, Fachuang; Ralph, John; Himmel, Michael E.; Balan, Venkatesh; Dale, Bruce E. 2011. Multi-scale visualization and characterization of lignocellulosic plant cell wall deconstruction during thermochemical pretreatment.
- Chundawat, Shishir P.S.; Bellesia, Giovanni; Uppugundla, Nirmal; da Costa Sousa, Leonardo; Gao, Dahai; Cheh, Albert M.; Agarwal, Umesh P.; Bianchetti, Christopher M.; Phillips, George N.; Langan, Paul; Balan, Venkatesh; Gnanakaran, S.; Dale, Bruce E. 2011. Restructuring the crystalline cellulose hydrogen bond network enhances its depolymerization rate.
- Agarwal, Umesh P. 2010. Advancing Raman spectroscopy for lignin applications.
- Agarwal, Umesh P.; Sabo, R.; Reiner, Richard S.; Clemons, Craig Merrill; Rudie, Alan W. 2009.
Raman analysis and mapping of cellulose nanocrystal-polypropylene composite.
- Agarwal, Umesh P.; Reiner, Richard S.; Beecher, James F. 2009.
Surface enhanced Raman spectroscopy for lignin analysis.
- Agarwal, Umesh P.; Reiner, Richard S.; Ralph, Sally A. 2009. Determination of cellulose I crystallinity by FT-Raman spectroscopy.
- Agarwal, Umesh P.; Reiner, Richard S. 2009. Near-Ir surface-enhanced Raman spectrum of lignin.
- Agarwal, Umesh P.; Ralph, Sally A. 2008. Determination of ethylenic residues in wood and TMP of spruce by FT-Raman spectroscopy.
- Agarwal, Umesh Prasad. 2008. Raman spectroscopic characterization of wood and pulp fibers.
- Agarwal, Umesh P. 2007. Higher acid-chlorite reactivity of cell corner middle lamella lignin in black spruce.
- Agarwal, Umesh P.; Ralph, Sally A. 2007. Revealing organization of cellulose in wood cell walls by Raman imaging.
- Agarwal, Umesh P.; Reiner, Richard S.; Ralph, Sally A. 2006. Using nano- and micro-particles of silver in lignin analysis.
- Agarwal, Umesh P. 2005. Predicting photoyellowing behaviour of mechanical pulp containing papers.
- Agarwal, Umesh P. 2005. Raman imaging of lignin and cellulose distribution in black spruce wood (Picea mariana) cell walls.
- Agarwal, Umesh P.; Reiner, Richard S.; Pandey, Ashok K.; Ralph, Sally A.; Hirth, Kolby C.; Atalla, Rajai H. 2005. Raman spectra of lignin model compounds.
- Bujanovic, Biljana; Reiner, Richard S.; Ralph, Sally A.; Agarwal, Umesh P.; Atalla, Rajai H. 2005. Structural changes of residual lignin of softwood and hardwood kraft pulp upon oxidative treatment with polyoxometalates.
- Agarwal, Umesh P.; Kawai, Nancy. 2005. “Self-absorption” phenomenon in near-infrared Fourier transform Raman spectroscopy of cellulosic and lignocellulosic materials.
- Hunt, Chris; Yu, Xiaochun; Bond, James; Agarwal, Umesh; Atalla, Raj. 2003. Aging of printing and writing paper upon exposure to light. Part 2, Mechanical and chemical properties.
- Agarwal, Umesh; Kawai, Nancy. 2003. FT-Raman spectra of cellulose and lignocellulose materials : “self-absorption” phenomenon and its implications for quantitative work.
- Agarwal, Umesh P.; Terashima, Noritsugu. 2003. FT-Raman study of dehydrogenation polymer (DHP) lignins.
- Agarwal, Umesh; Ralph, Sally A. 2003. In situ quantitation of ring-conjugated ethylenic lignin-units in spruce thermomechanical pulps by FT-Raman spectroscopy.
- Isogai, Akira; Agarwal, Umesh P.; Atalla, Rajai H. 2003. Raman microprobe analysis of single ramie fiber during mercerization.
- Agarwal, Umesh P. 2000. Ranking mechanical pulps for their potential to photoyellow.
- Agarwal, Umesh P.; McSweeny, James D.; Ralph, Sally A. 1999. An FT-raman study of softwood, hardwood, and chemically modified black spruce MWLS.
- Agarwal, Umesh P. 1999. On the importance of hydroquinone/p-quinone redox system in the photoyellowing of mechanical pulps.