ORCID Profile
0000-0001-7002-9034
Current Organisations
National Renewable Energy Laboratory
,
Colorado State University
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Publisher: Springer Science and Business Media LLC
Date: 27-08-2015
Publisher: Springer Science and Business Media LLC
Date: 12-02-2018
DOI: 10.1038/NBT.4067
Abstract: Cell walls in crops and trees have been engineered for production of biofuels and commodity chemicals, but engineered varieties often fail multi-year field trials and are not commercialized. We engineered reduced expression of a pectin biosynthesis gene (Galacturonosyltransferase 4, GAUT4) in switchgrass and poplar, and find that this improves biomass yields and sugar release from biomass processing. Both traits were maintained in a 3-year field trial of GAUT4-knockdown switchgrass, with up to sevenfold increased saccharification and ethanol production and sixfold increased biomass yield compared with control plants. We show that GAUT4 is an α-1,4-galacturonosyltransferase that synthesizes homogalacturonan (HG). Downregulation of GAUT4 reduces HG and rhamnogalacturonan II (RGII), reduces wall calcium and boron, and increases extractability of cell wall sugars. Decreased recalcitrance in biomass processing and increased growth are likely due to reduced HG and RGII cross-linking in the cell wall.
Publisher: Springer Science and Business Media LLC
Date: 03-01-2017
Publisher: Springer Science and Business Media LLC
Date: 17-01-2018
Publisher: Springer Science and Business Media LLC
Date: 07-01-2015
Publisher: Frontiers Media SA
Date: 28-04-2016
Publisher: Oxford University Press (OUP)
Date: 27-06-2014
Publisher: Springer Science and Business Media LLC
Date: 12-03-2015
Publisher: Springer Science and Business Media LLC
Date: 21-01-2016
Publisher: Wiley
Date: 14-11-2014
Abstract: Sucrose synthase (SUS) converts sucrose and uridine di-phosphate (UDP) into UDP-glucose and fructose. UDP-glucose is used by the cellulose synthase to produce cellulose for cell wall biosynthesis. For lignocellulosic feedstocks such as switchgrass, the manipulation of cell walls to decrease lignin content is needed to reduce recalcitrance of conversion of biomass into biofuels. Of perhaps equal importance for bioenergy feedstocks is increasing biomass. Four SUS genes were identified in switchgrass. Each gene contained 14 or 15 introns. PvSUS1 was expressed ubiquitously in the tissues tested. PvSUS2 and PvSUS6 were highly expressed in internodes and roots, respectively. PvSUS4 was expressed in low levels in the tissues tested. Transgenic switchgrass plants overexpressing PvSUS1 had increases in plant height by up to 37%, biomass by up to 13.6%, and tiller number by up to 79% compared to control plants. The lignin content was increased in all lines, while the sugar release efficiency was decreased in PvSUS1-overexpressing transgenic switchgrass plants. For switchgrass and other bioenergy feedstocks, the overexpression of SUS1 genes might be a feasible strategy to increase both plant biomass and cellulose content, and to stack with other genes to increase biofuel production per land area cultivated.
Publisher: Frontiers Media SA
Date: 20-07-2015
Publisher: Humana Press
Date: 2012
DOI: 10.1007/978-1-61779-956-3_17
Abstract: Cell wall recalcitrance is the largest contributor to the high expense of lignocellulose conversion to biofuels (Himmel ME et al., Science 315:804-807, 2007). In response to this problem, researchers at the BioEnergy Science Center (BESC) are working to determine the contributing factors of biomass recalcitrance. The primary approach to this is screening large s le sets of genetic and environmental variants of model and feedstock plant species for differences in recalcitrance to combined hydrothermal pretreatment and enzymatic hydrolysis (Decker S et al., BioEnergy Res 2:179-192, 2009). To handle these large s le sets (up to several thousand s les per set), the BESC has developed high throughput screening systems to evaluate both cell wall composition and recalcitrance (Selig MJ et al., Biotechnol Lett 33:961-967, 2011 Selig MJ et al., Ind Biotechnol 6, 104-111, 2010). Molecular beam mass spectroscopy and high throughput, 2-stage acid hydrolysis are used to determine amounts and ratios of cell wall components such as lignin, cellulose, and xylan. Recalcitrance is measured by glucose and xylose release after high throughput hydrothermal pretreatment and enzymatic saccharification, screening large numbers (up to 1,000 s per week) of biomass s les (Selig MJ et al., Ind Biotechnol 6, 104-111, 2010 Sykes R et al., Methods Mol Biol 581, 169-183, 2009). Implementation of these high throughput techniques revealed additional concerns when screening biomass s les for recalcitrance, principal among these was the contribution of starch to glucose release quantitation in both compositional analysis and recalcitrance screening.
Publisher: Elsevier BV
Date: 10-2016
Location: United States of America
Location: United States of America
No related grants have been discovered for Stephen Decker.