Author:
Shen Hui,Poovaiah Charleson R,Ziebell Angela,Tschaplinski Timothy J,Pattathil Sivakumar,Gjersing Erica,Engle Nancy L,Katahira Rui,Pu Yunqiao,Sykes Robert,Chen Fang,Ragauskas Arthur J,Mielenz Jonathan R,Hahn Michael G,Davis Mark,Stewart C Neal,Dixon Richard A
Abstract
Abstract
Background
Lignocellulosic biomass is one of the most promising renewable and clean energy resources to reduce greenhouse gas emissions and dependence on fossil fuels. However, the resistance to accessibility of sugars embedded in plant cell walls (so-called recalcitrance) is a major barrier to economically viable cellulosic ethanol production. A recent report from the US National Academy of Sciences indicated that, “absent technological breakthroughs”, it was unlikely that the US would meet the congressionally mandated renewable fuel standard of 35 billion gallons of ethanol-equivalent biofuels plus 1 billion gallons of biodiesel by 2022. We here describe the properties of switchgrass (Panicum virgatum) biomass that has been genetically engineered to increase the cellulosic ethanol yield by more than 2-fold.
Results
We have increased the cellulosic ethanol yield from switchgrass by 2.6-fold through overexpression of the transcription factor PvMYB4. This strategy reduces carbon deposition into lignin and phenolic fermentation inhibitors while maintaining the availability of potentially fermentable soluble sugars and pectic polysaccharides. Detailed biomass characterization analyses revealed that the levels and nature of phenolic acids embedded in the cell-wall, the lignin content and polymer size, lignin internal linkage levels, linkages between lignin and xylans/pectins, and levels of wall-bound fucose are all altered in PvMYB4-OX lines. Genetically engineered PvMYB4-OX switchgrass therefore provides a novel system for further understanding cell wall recalcitrance.
Conclusions
Our results have demonstrated that overexpression of PvMYB4, a general transcriptional repressor of the phenylpropanoid/lignin biosynthesis pathway, can lead to very high yield ethanol production through dramatic reduction of recalcitrance. MYB4-OX switchgrass is an excellent model system for understanding recalcitrance, and provides new germplasm for developing switchgrass cultivars as biomass feedstocks for biofuel production.
Publisher
Springer Science and Business Media LLC
Subject
Management, Monitoring, Policy and Law,General Energy,Renewable Energy, Sustainability and the Environment,Applied Microbiology and Biotechnology,Biotechnology
Reference46 articles.
1. Wang M, Wu M, Huo H: Life-cycle energy and greenhouse gas emission impacts of different corn ethanol plant types. Environ Res Lett. 2007, 2: 024001-10.1088/1748-9326/2/2/024001.
2. Mosier N, Wyman C, Dale B, Elander R, Lee Y, Holtzapple M, Ladisch M: Features of promising technologies for pretreatment of lignocellulosic biomass. Bioresour Technol. 2005, 96: 673-686. 10.1016/j.biortech.2004.06.025.
3. Liu ZL, Blaschek HP: Biomass conversion inhibitors and in situ detoxification. Biomass to Biofuels: Strategies for Global Industries. Edited by: Vertès AA, Qureshi N, Blaschek HP, Yukawa H. 2010, Oxford, UK: Blackwell Publishing Ltd, 10.1002/9780470750025.ch12
4. McLaughlin SB, Adams Kszos L: Development of switchgrass (Panicum virgatum) as a bioenergy feedstock in the United States. Biomass Bioenergy. 2005, 28: 515-535. 10.1016/j.biombioe.2004.05.006.
5. Schmer MR, Vogel KP, Mitchell RB, Perrin RK: Net energy of cellulosic ethanol from switchgrass. Proceedings of the National Academy of Sciences USA. 2008, 105: 464-469. 10.1073/pnas.0704767105.
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