Biomass Refining Research Articles

Lignocellulosic Biomass Refining: A Review Promoting a Method to Produce Sustainable Hydrogen, Fuels, and Products

Lignocellulosic Biomass Refining: A Review Promoting a Method to Produce Sustainable Hydrogen, Fuels, and Products

Process and technoeconomic analysis of leading pretreatment technologies for lignocellulosic ethanol production using switchgrass

Six biomass pretreatment processes to convert switchgrass to fermentable sugars and ultimately to cellulosic ethanol are compared on a consistent basis in this technoeconomic analysis. The six pretreatment processes are ammonia fiber expansion (AFEX), dilute acid (DA), lime, liquid hot water (LHW), soaking in aqueous ammonia (SAA), and sulfur dioxide-impregnated steam explosion (SO 2). Each pretreatment process is modeled in the framework of an existing biochemical design model so that systematic variations of process-related changes are consistently captured. The pretreatment area process design and simulation are based on the research data generated within the Biomass Refining Consortium for Applied Fundamentals and Innovation (CAFI) 3 project. Overall ethanol production, total capital investment, and minimum ethanol selling price (MESP) are reported along with selected sensitivity analysis. The results show limited differentiation between the projected economic performances of the pretreatment options, except for processes that exhibit significantly lower monomer sugar and resulting ethanol yields.

Surface and ultrastructural characterization of raw and pretreated switchgrass

The US Department of Energy-funded Biomass Refining CAFI (Consortium for Applied Fundamentals and Innovation) project has developed leading pretreatment technologies for application to switchgrass and has evaluated their effectiveness in recovering sugars from the coupled operations of pretreatment and enzymatic hydrolysis. Key chemical and physical characteristics have been determined for pretreated switchgrass samples. Several analytical microscopy approaches utilizing instruments in the Biomass Surface Characterization Laboratory (BSCL) at the National Renewable Energy Laboratory (NREL) have been applied to untreated and CAFI-pretreated switchgrass samples. The results of this work have shown that each of the CAFI pretreatment approaches on switchgrass result in different structural impacts at the plant tissue, cellular, and cell wall levels. Some of these structural changes can be related to changes in chemical composition upon pretreatment. There are also apparently different structural mechanisms that are responsible for achieving the highest enzymatic hydrolysis sugar yields.

Biomass Refining Technology Team, Biomass Technology Research Center, National Institute of Advanced Industrial Science and Technology (AIST)

Biomass Refining Technology Team, Biomass Technology Research Center, National Institute of Advanced Industrial Science and Technology (AIST)

Selected Process Alternatives for Biomass Refining: A Review

The role of biorefineries in the production of energy and chemicals from biomass of lignocellulosic nature is reviewed. Special attention is devoted to biorefinery schemes dealing with the fractionation of lignocellulosic raw materials by chemical treatments. The potential of hydrothermal treatments as the first stage of future biorefineries is discussed. Special attention is devoted to the low-volume, high-added value products that can be solubilized by this type of technology.

Summary of findings from the Biomass Refining Consortium for Applied Fundamentals and Innovation (CAFI): corn stover pretreatment

The Biomass Refining Consortium for Applied Fundamentals and Innovation, with members from Auburn University, Dartmouth College, Michigan State University, the National Renewable Energy Laboratory, Purdue University, Texas A&M University, the University of British Columbia, and the University of California at Riverside, has developed comparative data on the conversion of corn stover to sugars by several leading pretreatment technologies. These technologies include ammonia fiber expansion pretreatment, ammonia recycle percolation pretreatment, dilute sulfuric acid pretreatment, flowthrough pretreatment (hot water or dilute acid), lime pretreatment, controlled pH hot water pretreatment, and sulfur dioxide steam explosion pretreatment. Over the course of two separate USDA- and DOE-funded projects, these pretreatment technologies were applied to two different corn stover batches, followed by enzymatic hydrolysis of the remaining solids from each pretreatment technology using identical enzyme preparations, enzyme loadings, and enzymatic hydrolysis assays. Identical analytical methods and a consistent material balance methodology were employed to develop comparative sugar yield data for each pretreatment and subsequent enzymatic hydrolysis. Although there were differences in the profiles of sugar release, with the more acidic pretreatments releasing more xylose directly in the pretreatment step than the alkaline pretreatments, the overall glucose and xylose yields (monomers + oligomers) from combined pretreatment and enzymatic hydrolysis process steps were very similar for all of these leading pretreatment technologies. Some of the water-only and alkaline pretreatment technologies resulted in significant amounts of residual xylose oligomers still remaining after enzymatic hydrolysis that may require specialized enzyme preparations to fully convert xylose oligomers to monomers.

Biopolyester Synthesis and Protein Regulations in <I>Ralstonia eutropha</I> on Levulinic Acid and Its Derivatives from Biomass Refining

Biopolyester Synthesis and Protein Regulations in <I>Ralstonia eutropha</I> on Levulinic Acid and Its Derivatives from Biomass Refining

Comparative sugar recovery and fermentation data following pretreatment of poplar wood by leading technologies

Through a Biomass Refining Consortium for Applied Fundamentals and Innovation among Auburn University, Dartmouth College, Michigan State University, the National Renewable Energy Laboratory, Purdue University, Texas A&M University, the University of British Columbia, and the University of California at Riverside, leading pretreatment technologies based on ammonia fiber expansion, aqueous ammonia recycle, dilute sulfuric acid, lime, neutral pH, and sulfur dioxide were applied to a single source of poplar wood, and the remaining solids from each technology were hydrolyzed to sugars using the same enzymes. Identical analytical methods and a consistent material balance methodology were employed to develop comparative performance data for each combination of pretreatment and enzymes. Overall, compared to data with corn stover employed previously, the results showed that poplar was more recalcitrant to conversion to sugars and that sugar yields from the combined operations of pretreatment and enzymatic hydrolysis varied more among pretreatments. However, application of more severe pretreatment conditions gave good yields from sulfur dioxide and lime, and a recombinant yeast strain fermented the mixed stream of glucose and xylose sugars released by enzymatic hydrolysis of water washed solids from all pretreatments to ethanol with similarly high yields. An Agricultural and Industrial Advisory Board followed progress and helped steer the research to meet scientific and commercial needs.

Biorefineries–Industrial Processes and Products: Status Quo and Future Directions

Biorefineries–Industrial Processes and Products: Status Quo and Future Directions

Coordinated development of leading biomass pretreatment technologies

For the first time, a single source of cellulosic biomass was pretreated by leading technologies using identical analytical methods to provide comparative performance data. In particular, ammonia explosion, aqueous ammonia recycle, controlled pH, dilute acid, flowthrough, and lime approaches were applied to prepare corn stover for subsequent biological conversion to sugars through a Biomass Refining Consortium for Applied Fundamentals and Innovation (CAFI) among Auburn University, Dartmouth College, Michigan State University, the National Renewable Energy Laboratory, Purdue University, and Texas A&M University. An Agricultural and Industrial Advisory Board provided guidance to the project. Pretreatment conditions were selected based on the extensive experience of the team with each of the technologies, and the resulting fluid and solid streams were characterized using standard methods. The data were used to close material balances, and energy balances were estimated for all processes. The digestibilities of the solids by a controlled supply of cellulase enzyme and the fermentability of the liquids were also assessed and used to guide selection of optimum pretreatment conditions. Economic assessments were applied based on the performance data to estimate each pretreatment cost on a consistent basis. Through this approach, comparative data were developed on sugar recovery from hemicellulose and cellulose by the combined pretreatment and enzymatic hydrolysis operations when applied to corn stover. This paper introduces the project and summarizes the shared methods for papers reporting results of this research in this special edition of Bioresource Technology.