Progress in understanding and overcoming biomass recalcitrance: a BioEnergy Science Center (BESC) perspective

Biotechnology for Biofuels, Dec 2017

The DOE BioEnergy Science Center has operated as a virtual center with multiple partners for a decade targeting overcoming biomass recalcitrance. BESC has redefined biomass recalcitrance from an observable phenotype to a better understood and manipulatable fundamental and operational property. These manipulations are the result of deeper biological understanding and can be combined with other advanced biotechnology improvements in biomass conversion to improve bioenergy processes and markets. This article provides an overview of key accomplishments in overcoming recalcitrance via better plants, better microbes, and better tools and combinations. A perspective on the aspects of successful center operation is presented.

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Progress in understanding and overcoming biomass recalcitrance: a BioEnergy Science Center (BESC) perspective

Gilna et al. Biotechnol Biofuels Progress in understanding and overcoming biomass recalcitrance: a BioEnergy Science Center (BESC) perspective Paul Gilna 0 2 3 Lee R. Lynd 0 1 2 Debra Mohnen 0 2 5 Mark F. Davis 0 2 4 Brian H. Davison 0 2 3 0 Biosciences Division, Oak Ridge National Laboratory , 1 Bethel Valley Road, Bldg. 1505, Rm. 100A, Oak Ridge, TN 37831‐6037 , USA 1 Thayer School of Engineering, Dartmouth College , Hanover, NH 03755 , USA 2 Biosciences Division, Oak Ridge National Laboratory , 1 Bethel Valley Road, Bldg. 1505, Rm. 100A, Oak Ridge, TN 37831‐6037 , USA 3 BioEnergy Science Center, Oak Ridge National Laboratory , Oak Ridge, TN 37831 , USA 4 National Bioenergy Center, National Renewable Energy Laboratory , Golden, CO 80401 , USA 5 Complex Carbohydrate Research Center and Department of Biochemis‐ try and Molecular Biology, University of Georgia , Athens, GA 30602 , USA The DOE BioEnergy Science Center has operated as a virtual center with multiple partners for a decade targeting overcoming biomass recalcitrance. BESC has redefined biomass recalcitrance from an observable phenotype to a better understood and manipulatable fundamental and operational property. These manipulations are the result of deeper biological understanding and can be combined with other advanced biotechnology improvements in biomass conversion to improve bioenergy processes and markets. This article provides an overview of key accomplishments in overcoming recalcitrance via better plants, better microbes, and better tools and combinations. A perspective on the aspects of successful center operation is presented. Bioconversion; Bioenergy; Recalcitrance; Center operation; Biomass Background Biomass recalcitrance—the resistance of plants to release their sugars for fermentation or upgrading—is a primary barrier to efficient and economical production of advanced biofuels [ 1, 2 ]. Overcoming and understanding recalcitrance was the unifying vision of the US Department of Energy (DOE) BioEnergy Science Center (BESC), now in its final and 10th year of operation. The mission of BESC was “to enable the emergence of a sustainable cellulosic biofuels industry by leading advances in science and science-based innovation resulting in removal of recalcitrance as an economic barrier to cost-effective production of biofuels [3].” Due to advances in biotechnology, BESC believed that biological solutions were the most promising path by which to achieve these breakthroughs. In response to a DOE challenge [ 4 ], Oak Ridge National Laboratory (ORNL) led the formation of BESC by gathering experienced researchers from multiple US institutions, who had been separately interested in separate aspects of overcoming biomass recalcitrance targeting advanced biofuels and specifically cellulosic ethanol. Recalcitrance began as an operationally defined phenotype. With both applied and fundamental goals, BESC perceived that we needed to transform the understanding of recalcitrance; this required detailed knowledge of the chemical, structural, and physical properties of biomass and how these properties influenced deconstruction by enzymes and thermophilic microorganisms. This search led to altering plant cell wall properties by manipulating key plant polymer biosynthetic pathways, which led to studies of the interactions of the plant cell walls and the enzymes and microbes during deconstruction and fermentation. The BESC team has redefined recalcitrance so that now recalcitrance is on the path to being an understandable and manipulatable set of properties based on cell wall formation and bioconversion. A key outcome of the BESC team’s approach was to transform understanding in both fundamental and operational impacts to strategies that will eliminate recalcitrance as an economic barrier to commercialization. This singular focus on recalcitrance science was BESC’s hallmark worldwide. BESC was organized into three areas: Biomass Formation and Modification, Biomass Deconstruction and Conversion, and Enabling Technologies (Fig. 1). All three areas included both fundamental understanding and complementary proof-ofconcept components. Our ability to design, conduct, and analyze wide-ranging campaigns, along with our effective communications and capacity to integrate cross-disciplinary teams within the BESC organization, has been key to our success in scientific areas that are critical to overcoming the formidable biological and technological barriers that biomass recalcitrance presents. Discussion: major accomplishments to date From late 2007 to fall  2017, BESC published more than 945 journal articles, 10% in high-profile journals (impact factor > 9) and advanced the education of more than 230 professionals, who are now productive members of the bioeconomy workforce. More details with respect to the output of BESC and the other two USDOE Bioenergy Research Centers are in Slater et al. [ 5 ]. Biomass formation Populus and switchgrass (Panicum vir (...truncated)


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Paul Gilna, Lee R. Lynd, Debra Mohnen, Mark F. Davis, Brian H. Davison. Progress in understanding and overcoming biomass recalcitrance: a BioEnergy Science Center (BESC) perspective, Biotechnology for Biofuels, pp. 285,