title: Sodium hydroxide pretreatment of genetically modified switchgrass for improved enzymatic release of sugars.
abstract: Overcoming biomass recalcitrance to bioconversion is crucial for cellulosic biofuels commercialization. In this study, Alamo switchgrass (Panicum virgatum L.) was genetically transformed to suppress the expression of 4-coumarate-CoA ligase (4CL). The transgenic plants were determined to have lignin content reductions of up to 5.8%. The ratios of acid soluble lignin (ASL) to acid insoluble lignin (AIL) and syringyl/guaiacyl (S/G) in transgenic plants were 21.4-64.3% and 11.8-164.5%, respectively, higher than those of conventional biomass. Both conventional and transgenic plants were pretreated with 0.5%, 1%, and 2% (w/v) NaOH for 15, 30, and 60min at 121°C, followed by enzymatic hydrolysis with commercial cellulases and xylanases. At the optimal conditions, the glucan and xylan conversion efficiency in the best transgenic plants were 16% and 18% higher than the conventional plant, respectively. The results show that down-regulation of 4CL gene promoted enzymatic hydrolysis of plant cell walls following a mild alkali pretreatment.
authors.affiliation: Department of Biological and Agricultural Engineering, North Carolina State University, Raleigh, NC 27695-7625, USA.
authors.forename: Ziyu
authors.initials: Z
authors.lastname: Wang
authors.forename: Ruyu
authors.initials: R
authors.lastname: Li
authors.forename: Jiele
authors.initials: J
authors.lastname: Xu
authors.forename: Jane M
authors.initials: JM
authors.lastname: Marita
authors.forename: Ronald D
authors.initials: RD
authors.lastname: Hatfield
authors.forename: Rongda
authors.initials: R
authors.lastname: Qu
authors.forename: Jay J
authors.initials: JJ
authors.lastname: Cheng
mesh_terms: D018533:Biomass; D050260:Carbohydrate Metabolism; D006868:Hydrolysis; D030821:Plants, Genetically Modified; D006109:Poaceae / Q000235:genetics / Q000378:metabolism*; D012972:Sodium Hydroxide / Q000737:chemistry*
chemical_list: D012972:Sodium Hydroxide