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Sodium hydroxide pretreatment of genetically modified switchgrass for improved enzymatic release of sugars

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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 60 min 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.
Wang, Ziyu , Li, Ruyu , Xu, Jiele , Marita, Jane M. , Hatfield, Ronald D. , Qu, Rongda , Cheng, Jay J.
Panicum virgatum , alkalis , biomass , biotransformation , cell walls , cellulases , commercialization , coumarate-CoA ligase , enzymatic hydrolysis , gene expression regulation , genes , lignin , pretreatment , sodium hydroxide , sugars , transgenic plants , xylanases
Includes references
Bioresource technology 2012 Apr., v. 110
Journal Articles, USDA Authors, Peer-Reviewed
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