Feedstock Development programs
Understanding the Molecular Basis for Plant Cell Wall Recalcitrance to Degradation
This program seeks to understand how lignocellulose in the cell wall is degraded by analyzing the structure of that biomass before degradation. The team uses various chemical approaches to describe structural properties of the cell wall. The lab applies these approaches in characterizing unique plant feedstocks generated by the group.
The objective of this program is to describe structural features of plant lignocellulosics that play a role in making this renewable material recalcitrant to enzymatic and/or chemical degradation and conversion. The identified parameters can lead to the generation of plant feedstocks with desirable attributes, including but not limited to increasing the abundance of sugars in the material, increasing accessibilities to sugars, or reducing material-based process inhibitors. Together with the knowledge of the underlying plant genetics in bioenergy crops, those parameters provide targets for marker-assisted breeding. Moreover, the data can lead to models for improvement in biomass processing, i.e. lowering chemical and energy requirements while increasing sugar yields based on first principles rather than empiric trials. To achieve this goal, the program was split in 2014 into three distinct yet complementary projects: i) the continuous utilization of 2D-NMR to describe the structural alterations of lignocellulosics; ii) identification of plant esterases that when knocked out lead to an increase in lignocellulosic acetylation; replacement of O-acetyl-substituents with glycosyl-residues lead to plant biomass with low acetate content, but regular biomass accumulation; iii) screening a genetically diverse sorghum population, which did not identify strong QTLs for lignocellulosic compositional traits.
The overall objective of this program is to identify structural features of plant lignocellulosics that play a role in making this renewable material recalcitrant to enzymatic and/or chemical degradation. The identified parameters can lead to the generation of plant feedstocks with desirable attributes. Understanding the structural changes that happen during processing of lignocellulosic materials requires knowledge of the entire structure in the material. One method we have developed is a lignocellulosic dissolution method for 2D-NMR analysis, involving an organic solvent with the addition of a deuterated ionic liquid. Assessing the structural diversity of lignocellulosic-based energy crops with this method indicated that grass vs. wood is the most prominent diversity factor.
A non-transgenic maize mutant (Cal-1) had been identified with a higher glucan content compared to a wild-type variety. Field trials of Cal-1 performed in Illinois by collaborator Pat Brown indicated that the Cal-1 mutation neither leads to yield losses in dry kernel nor dry biomass weight. Cal-1 was crossed to maize brownmidrib (bm) mutants that are affected in lignin content and/or composition. The saccharification yields from corn stover of the double mutants are massively increased to 60% glucose yields compared to the wild-type varieties.
One of the inhibitors present in lignocellulosics for yeast-based fermentation is acetate, which is released upon biomass processing. The goal of this project is to investigate the molecular mechanism of polymer O-acetylation in the plant to open avenues of how to reduce this inhibitor. We have now identified a hemicellulose O-acetyltransferase. Knocking out this gene in the model plant system Arabidopsis led to reduction of lignocellulosic acetate by more than 50%, but the plant was stunted in growth and saccharification yields from biomass material were lower, hinting an important physiological function of this acetate substituent.
Pauly’s work probes the structural diversity of lignocellulose that a biorefinery might encounter and has revealed that tissue within a plant – leaf tissue versus stem tissue, for example – varies greater than between plants grown in different locations. In another project, Pauly’s group found a single base-pair mutation that causes the increased production of a specific polysaccharide that typically exists only in the walls of young plant tissues. This polysaccharide, which has a much higher glucose yield than wild-type maize leaf material, also appears to increase the accessibility of wall polysaccharides to enzymes, a potential benefit to biofuel production. Finally, Pauly’s team identified a gene that prevents the creation of acetate, a common byproduct in biomass fermentation that inhibits the action of yeast, in xyloglucan, a type of hemicellulose.
A maize mutant was identified (candy leaf 1; Cal-1) that contains elevated levels of easily digestable glucans, increasing saccharification yields by 30-35%.
Published in 2014
Characterization of the Distinct Plant Pectin Esterases PAE8 and PAE9 and its Mutants, A. de Souza, P. A. Hull, S. Gille, M. Pauly, Planta, V. 240 (5), pp. 1123-1138, August 13, 2014.
Structural Diversity and Function of Xyloglucan Sidechain Substituents, Alex Schultink, Lifeng Liu, Lei Zhu, Markus Pauly, Plants, doi: 10.3390/plants3040526, November 2014.
Published in 2013
Solution-State 2D NMR Spectroscopy of Plant Cell Walls Enabled by a DMSO-d6[Emim]OAc Solvent, K. Cheng, H. Sorek, H. Zimmermann, D. E. Wemmer, M. Pauly, 2013, Analytical Chemistry, 85 (6), pp. 3213-3221.
Xylan O-Acetylation Impacts Xylem Development and Enzymatic Recalcitrance as Indicated by the Arabidopsis Mutant Tbl29, Guangyan Xiong, Kun Cheng, Markus Pauly, Molecular Plant 6(4), pp. 1373-1375, doi: 10.1093/mp/sst014, April 2013.
Arabinosylation of a Yariv-Precipitable Cell Wall Polymer Impacts Plant Growth as Exemplified by the Arabidopsis Glycosyltransferase Mutant ray 1, M. Dwiyanti, S. Gille, V. Sharma, EE Baidoo, JD Keasling, HV Scheller, M. Pauly, Molecular Plant, May 17, 2013 online.
Hemicellulose Biosynthesis, Markus Pauly, Sascha Gille, Lifeng Liu, Nasim Mansoori, Amancio De Souza, Alex Schultink, Planta 238(4), pp. 327-342, doi: 10.1007/s00425-013-1921-1, June 14, 2013.
Reduced Wall Acetylation Proteins Play Vital and Distinct Roles in Cell Wall O-Acetylation in Arabidopsis, Yuzuki Manabe, Yves Verhertbruggen, Sascha Gille, Jesper Harholt, Sun-Li Chong, Prashant Mohan-Anupama Pawar, Exa J. Mellerowicz, Maija Tenkanen, Kun Cheng, Markus Pauly, Henrik Vibe Scheller, Plant Physiology, doi: 10.1104/pp.113.225193, September 2013.
Two-Step Delignification of Miscanthus to Enhance Enzymatic Hydrolysis: Aqueous Ammonia Followed by Sodium Hydroxide and Oxidants, Zhongguo Liu, Sasisanker Padmanabhan, Kun Cheng, Philippe Schwyter, Markus Pauly, Alexis Bell, John M. Prausnitz, Bioresource Technology, October 9, 2013.
RWA Proteins Play Vital and Distinct Roles in Cell Wall O-Acetylation in Arabidopsis thaliana, Y. Manabe, Y. Verhertbruggen, S. Gille, J. Harbolt, S. L. Chong, P. Pawar, E. Mellerowicz, M. Tenkanen, K. Cheng, M. Pauly, H. V. Scheller, Plant Physiology 163(3), pp. 1107-1117, November 2013.
A β–glucuronosyltransferase from Arabidopsis thaliana Involved in Biosynthesis of Type II Arabinogalactan Has a Role in Cell Elongation During Seedling Growth, Eva Knoch, Adiphol Dilokpimol, Theodora Tryfona, Christian P. Poulsen, Guangyan Xiong, Jesper Harholt, Bent L. Petersen, Peter Ulvskov, Masood Z. Hadi, Toshihisa Kotake, Yoichi Tsumuraya, Markus Pauly, Paul Dupree, Naomi Geshi, Plant Journal 76 (6), pp. 1016-1029, doi: 10.1111/tpj.12353, December 2013.
Published in 2012
Aqueous-Ammonia Delignification of Miscanthus Followed by Enzymatic Hydrolysis to Sugars, Zhongguo Liu, Sasisanker Padmanabhan, Kun Cheng, Phillipe Schwyter, Markus Pauly, Alexis Bell, John M. Prausnitz, Biosource Technology, dx.doi.org/10.1016/j.biotech.2012.10.133, November 5, 2012.
XAXTI, a Grass-Specific Xylan: Xylosyltransferase in the Glycotransferase Family 61, D. Chiniquy, V. Sharma, A. Schultink, E. E. Baidoo, C. Rautengarten, K. Cheng, A. Carroll, P. Ulvskov, J. Harholt, J. D. Keasling, M. Pauly, H. V. Scheller, P. C. Ronald, Crop Science 52 (6) 2687-2701, doi: 10.1073, Proceedings of the National Academy of Sciences, 109 (42), 17117-17122, October 2012.
RNA-Seq. of Developing Nasturtium Seeds (Tropaeolum majus): Identification and Characterization of an Additional Glactosyltransferase Involved in Xyloglucan Biosynthesis, J. K. Jensen, A. Schultink, K. Keegstra, C. G. Wilkerson, M. Pauly, Molecular Plant 5 (5) 984-992, doi: 10.1093/mp/sss032, September 2012.
Down-Regulation of Maize Cinnamoyl-CoA Reductase via RNAi Technology Creates Brown Midrib and Improves AFEX-Pretreated Conversion into Fermentable Sugars for Biofuels, S. H. Park, C. Mei, M. Pauly, R. G. Ong, B. E. Dale, R. Sabzikar, H. Fotoh, T. Nguyen, M. Sticklen, Crop Science 52 (6) 2687-2701, doi: 10.2135, June 2012 online.
O-acetylation of Plant Cell Wall Polysaccharides, S. Gille, M. Pauly, Frontiers in Plant Science Physiology 3: 12, doi: 10.3389/fpls.2012.00012, Janary 2012 online.
Reduction in Xylan 0-acetylation Results in Increased Recalcitrance to Saccharification as Indicated by the Arabidopsis Mutant tb129 , G. Xiong, K. Cheng, M. Pauly, Molecular Plant (in press).
Published in 2011
O-Acetylation of Arabidopsis Hemicellulose Xyloglucan Requires AXY4L, Proteins with a TBL and DUF231 Domain, Sascha Gille, Amancio de Souza, Guangyan Xiong, Monique Benz, Kun Cheng, Alex Schultink, Ida-Barbara Reca, Markus Pauly, The Plant Cell, doi: 10.1105/tpc.111.091728, November 15, 2011.
Overexpression of the Maize Corngrass1 MicroRNA Gene Prevents Flowering, Improves Digestability and Increases Starch Content of Switchgrass, George Chuck, Christian Tobias, Florian Kraemer, Chenlin Li, Dean Dibble, Rohit Arora, Jennifer Bragg, John Vogel, Seema Singh, Blake Simmons, Markus Pauly, Sarah Hake, Proceedings of the National Academy of Sciences, 108 (42), pp. 17550-17555, doi: 10.1073/pnas.1113971108, October 10, 2011.
Deep Sequencing of Voodoo Lily (Amorphophallus konjac): an Approach to Identify Relevant Genes Involved in the Synthesis of the Hemicellulose Glucomannan, Sascha Gille, Kun Cheng, Mary E. Skinner, Aaron Liepman, Curtis Wilkerson, Markus Pauly, Planta, doi:10.1007/s00425-011-1422-z, May 3, 2011.