2005 OBP Biennial Peer Review

Pretreatment & Enzymatic Hydrolysis

Rick Elander (NREL)

Biochemical Conversion Platform

November 15, 2005

2.0Biochemical Platform

2.1Pretreatment and

Enzymatic Hydrolysis

2.2Feedstock-Biochemical

Interface

2.3Process Integration

2.4Targeted Conversion

2.5Biochemical Platform

Analysis 2.1.1

Pretreatment and Enzymatic Hydrolysis

2.1.1.1CAFI 2 Support

2.1.1.2Feedstock Qualification

2.1.1.2.1Extended Fiber

Pretreatment

2.1.1.3Forest Biorefinery

2.1.1.4Enzymatic Hydrolysis

2.1.1.5Exploratory Pretreatment

2.1.3Integration of Leading Biomass PretreatmentTechnologies (CAFI 2)

2.2.4 Preprocessing and Storage Systems

Development/Qualification

2.2.5Preprocessing Feedstock

Supply

2.3.1 Processing Integration

2.4.1Targeted Conversion

Research

2.4.1.1 Chemical Conversion

Fundamentals2.4.2

Biological Processing Fundamentals

2.4.3Plant Cell Wall Deconstruction

2.4.4BSCL and Genomics

2.4.4Industrial Membrane

Filtration & Short BedFractal Separation

2.3.1Feedstock Variability

2.3.2Integrated Processing

2.3.3Analytical Methods

7.04.2.GO41221Rheology and CFD Modeling

NRELAcademiaIndustryEarmark

Work Breakdown Structure

Platform Fit with Pathways

Program Outputs

FeedstockR&D

SugarsR&D

ThermochemicalR&D

ProductsR&D (from)

•Residual Starch Conversion•Fiber Conversion

Systems-level demonstration and validation by 2009

Corn Wet Mill Improvements

(Corn)

Element Strategic Goals

Corn Dry Mill Improvements(Corn, Grain)

Agricultural Residue Processing(Corn Stover, Wheat Straw, Rice Straw)

•Biomass Fractionation•Sugars Production

Sustainably supply biomass to

biorefineries

Low-cost sugars from lignocellulosic

biomass

Biomass Program Strategic Goal

Cost-competitive biorefinery technologies

for the nation’s transportation, chemical

and power industries

IntegratedBiorefineries

•Residual Starch Conversion•Fiber Conversion•Milled Grain Fractionation

Energy Crops(Perennial Grasses,

Woody Crops)

Pulp and Paper Mill Improvements

(Mill Wastes, Wood)•New Fractionation Processfor hemiicellulose removal

Chemical building blocks from

lignocellulosic biomass

Fuels, chemicals and power from bio-based sugars and chemical

building blocks

Systems-level demonstration and validation by 2012

Systems-level demonstration and validation by TBD

Systems-level demonstration and validation by TBD

Systems-level demonstration and validation by 2010

•Biomass Fractionation•Sugars Production

• Aventine/Purdue

• CAFI 2• Feedstock Qualification• Enzymatic Hydrolysis• Exploratory (Prt.) Sacch.• Rheology/CFD Modeling

• CAFI 2• Feedstock Qualification• Exploratory (Prt.) Sacch.

• Forest Biorefinery (Hemicellulose Ext.)

Barriers

Commercial Success Barriers

Price of Sugars from “Cellulosic” Biomass

Major General BarriersFeedstock Cost

Sugars CompositionSugars Yield

Conversion RateSugars Quality

Capital Investment

R&D Technical BarriersFeedstock-Sugars Interface

Biomass PretreatmentEnzymatic Hydrolysis

Sugars ProcessingProcess Integration

• Biomass Recalcitrance• New Pathways• Enabling Tools

University of Louisville

CAFI 2

Pretreatment & Enzymatic Hydrolysis

Targeted Conversion Research

Sugar Process Integration

Sugar Platform Analysis

$3,127K

$2,025K

$3,014K

$205K$295K

$628K

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Overview

Budget (FY05)• NREL (Pretreatment and Enzymatic Hydrolysis Task)• Aventine/Purdue University• CAFI Universities

– Auburn University– Dartmouth College– Michigan State University– Purdue University– Texas A&M University

– University of British Columbia • Neoterics Int’l.• Harris Group Inc.• Novozymes • Genencor Int’l.• Merrick & Co.• University of Louisville

Partners

Approach

• Overall Goal: Enable less severe (less costly) pretreatment and more economical enzymatic hydrolysis/sugar production

• Understand how pretreatment alters biomass structure and composition

• Assess required enzyme loadings and types

• Understand response of feedstock types representing several pathways

• Across different pretreatment processes and ranges of severities

• Role of non-cellulase enzymes

• High solids pretreatment and saccharification

2.1.Pretreatment and

EnzymaticHydrolysis

2.3.Processing Integration

2.4. Targeted

Conversion Research

Pretreatment and Enzymatic Hydrolysis Projects

• Projects Supporting Near Term Biorefinery Opportunities• Bridge to Corn Ethanol Project (Aventine/Purdue) • Hemicellulose Extraction Subtask (NREL)

• Pretreatment Effects on Feedstock Structure and Types• Exploratory Saccharification Subtask (NREL)• Feedstock Qualification Subtask (NREL)• Integration of Leading Biomass Pretreatments Project (CAFI 2)

• Enzymatic Hydrolysis and High Solids Processing• Enzyme Subcontract Liaison Subtask (NREL)• Enzymatic Hydrolysis Subtask (NREL)• Rheology and CFD Modeling Project (Univ. Louisville)

Bridge to Corn Ethanol– Aventine/Purdue

• Objective: Demonstrate conversion of residual starch and lignocellulosic carbohydrates in wet mill corn fiber

• Work has progressed from bench scale to in-plant pilot-scale testing over 5 years (with technoeconomic analysis guidance)

• Simple, low cost approach that readily integrates into existing wet mill

• Economic risks mitigated by integrating into existing commercial facility

• Bench scale results and economic analysis decision points indicated sufficient potential to proceed to in-plant pilot testing at Aventine

• Broad multidisciplinary collaboration involving Aventine, Purdue, NREL, USDA, Illinois Corn Marketing Board

Bridge to Corn Ethanol– Aventine/Purdue

• Technical challenges focused on process validation at scale and equipment performance

• Material handling and heat transfer have proven challenging• Slurry viscosity spikes during initial heat-up, then falls during pretreatment

• Process robustness not yet validated for extended continuous operation• Modifications to heat exchanger, pump, and centrifuge underway to

enable more reliable operation

Forest Biorefinery--Hemicellulose Extraction

• Objective: Partially extract hemicellulose prior to chemical or thermomechanical pulping while retaining pulp quality• Solubilize enough sugars to permit economically viable ethanol production

• Limit risks by focusing on key issues of hemicellulosic sugar recovery yields and pulp properties• Address other R&D issues later (e.g., oligomer conversion, acetic acid

recovery, fermentation)

• Initial milestones on sugar yields and potential ethanol economics look attractive under certain scenarios (strongly influenced by assumptions about utility and enzyme costs)• Some issues concerning pulp quality identified (that are being addressed by

USDA FPL and academic participants in Agenda 2020 consortium)• Results to inform a go-no go decision for a “Stage 3” cost-shared industry-

led consortium project

Forest Biorefinery--Hemicellulose Extraction

Steam

Extract Liquor

Recirculating Chip Extractor

● Completed a series of hemicellulose extractions at various conditions for maple and spruce chips

● Preliminary economic analysis for ethanol production conducted

● Extracted chips supplied to the USDA’s Forest Product Lab to evaluate pulp quality

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Total Xylan Conversion

Xylan to Total Xylose

Xylan to Oligomer

Xylan to Monomer

Xylan to Furfural

Acetate to Acetic Acid

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Total Xylan Conversion

Xylan to Total Xylose

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Acetate to Acetic Acid

Run 4 Run 2 Run 1 Run 3Run 4 Run 2 Run 1 Run 3

Digester

Chip PilePre-

Digester

Ethanolor

Chemicals

FermentHemi-

celluloseSugars

Paper Products

Digester

Chip PilePre-

Digester

Ethanolor

Chemicals

FermentHemi-

celluloseSugars

Paper Products

Exploratory (Pretreatment) Saccharification

• Objective: Understand biomass ultrastructure effects• Pretreatment catalyst transport (corn stem as a model)

• Identify required enzyme activities as a function of pretreatment approach• Enable a less severe pretreatment that achieves high sugar yields

• Highly integrated with other subtasks in Pretreatment & Enzymatic Hydrolysis and Targeted Conversion tasks

• Feedstock Qualification subtask generates pretreated samples from different feedstock types across a range of pretreatment pHs/severities

• “Joint” milestone with Plant Cell Wall Deconstruction subtask (9/05)

• Leveraging “CAFI 2” comparative pretreatment project• Accessing “progressively” pretreated samples to understand how

composition and structure change as pretreatment proceeds (effect on enzyme loading and required enzyme activities)

Exploratory (Pretreatment) Saccharification

Corn stem xylem1.5% H2SO4,150oC, 20 min

Corn stem xylemNo pretreatment

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Spez(15) GCI MF Xylanse (10) Spez(15) Sigma XynA (3) Spez(15) BG 1000 (10)

Spez(15) Optimash BG(10)

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Spez(15) GCI MF Xylanse (10) Spez(15) Sigma XynA (3) Spez(15) BG 1000 (10)

Spez(15) Optimash BG(10)

Enzyme Augmentation Studies on ARP (CAFI) Pretreated Corn Stover

Surface Ultrastructure Changes Upon Dilute Acid Pretreatment

Feedstock Qualification

• Objective: Develop and apply a method for screening pretreatment pH and severity effects across feedstock types• Generate comparative pretreatment reactivity data for stakeholders

• Do not attempt to optimize performance of specific pretreatment processes

• Select feedstocks (beyond stover) based on “Billion Ton” study results• Switchgrass

• Wheat straw

• Representative forest biomass feedstock

• Complements other activities in Biochemical Platform• CAFI (broad reactivity screening as compared to specific pretreatment process

optimization)

• Exploratory Saccharification/Plant Cell Wall Deconstruction

• Sugar Processing Integration (platform for future integration of feedstock/pretreatment/enzyme combinations)

Feedstock Qualification

Initial Findings on Switchgrass Across Wide pH Range

• Standard methodology for pretreatment and enzymatic saccharification developed

• Initial data on switchgrass generated

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Pretreatment conditions

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d saccarification oligomerssaccarification monomerspretreatment oligomerspretreatment monomers

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Sand Baths for Reactor Heating

MultiClave 10-Well Reactor

Acidic( severity)

Neutral( sev.)

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Neut.( sev)

Alkaline( severity)

Integration of Leading Biomass Pretreatments (CAFI 2)

• Objective: Develop comparative performance data and process economics on selected leading pretreatment approaches using:

• Common feedstocks• Standardized enzymes• Identical procedures for sample analysis• Consistent methods for economic analyses, i.e., for material and energy balancing

and process cost estimation

• Build off of USDA-funded “CAFI 1” project into new areas• Corn stover and hybrid poplar feedstocks

• Enzyme activities and loadings matched to pretreated feedstocks

• Hydrolyzate fermentability at relevant sugar concentrations

• Rigor of economic models (esp. pretreatment area capital costs)

• Generate “progressively” pretreated samples• Facilitate core OBP R&D in the Exploratory Saccharification and Plant Cell Wall

Deconstruction subtasks

Integration of Leading Biomass Pretreatments (CAFI 2)

Comparative Sugar Yields and Process Economics from “CAFI 1” Data

• Hybrid poplar is more difficult to effectively pretreat and saccharify• Especially for alkaline pretreatments

• Commercial xylanase addition can result in higher xylose AND glucose yields at same overall protein loading as “cellulase only” enzyme cocktail

• Especially for alkaline and neutral pretreatments

• Process modeling updates underway (initial milestone in June, 2006)

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Dilute Acid Hot Water AFEX ARP Lime

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w/o Oligomer Credit w/ Oligomer Credit

Initial Findings from “CAFI 2” Project

Dilute Acid

Hot Water

AFEXARP LimeFlow-

through

Enzyme Subcontract Liaison

• Objective: Support and validate enzyme cost reduction by enzyme manufacturers (Novozymes and Genencor)

• Supply “standard” substrate (dilute acid pretreated corn stover, PCS)

• Develop cost metric to translate performance into economic terms, i.e., enzyme cost ($/gallon EtOH)

• Experimentally validate improved enzyme performance

• Review/Audit achievements in reducing enzyme production costs

• Contracts with two enzyme companies reduces risk• Different approaches, different means of achieving cost reduction

• Improved enzyme production economics• Improved specific activity

• NREL improvements to high solids, dilute acid pretreatment process contributed to enzyme cost reduction

Enzyme Subcontract Liaison

Pretreated Corn Stover (PCS) Substrate Improvements

• Enzyme Subcontract Liaison activities completed in FY05• Verified reduction of cellulase costs to less the $0.20/gallon EtOH (per

enzyme cost metric) for both Novozymes and Genencor • 20-30X improvement from starting benchmark

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Benchmark prep

Soluble Protein Loading (mg protein/g cellulose)%

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Example SSF Performance Assay Results --Improved Preparation

Benchmark prep

Improved Enzyme Preparation on Pretreated Corn Stover (PCS)

Example SSF Performance Assay Results-- Improved Substrate

Enzymatic Hydrolysis

• Objective: Develop processing knowledge to enable high solids enzymatic saccharification

• Understand impacts of background sugars and other inhibitors

• Characterize rheology and mixing characteristics of high solid slurries to facilitate design of commercial equipment

• Identify commercial reactor systems and develop cost information

• Will test whole slurry conversion using advanced enzymes

• Evaluate solid phase properties during hydrolysis (particle size, crystallinity, rheology, pore size distribution) and relate to kinetics

• Investigate fundamental factors affecting rheology

• Identify promising commercial reactor systems

Enzymatic Hydrolysis

High solids processing can significantly reduce capital and operating costs

Testing a High Solids Bioreactor (HSBR) and comparing to fed batch solids addition to a stirred tank bioreactor

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Total Solids to Saccharification (wt. % )

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Rheology and CFD Modeling—Univ. Louisville

• Objective: Use Computational Fluid Dynamics (CFD) modeling to improve design of pretreatment, saccharification, and fermentation reactors

• High solids conditions

• Changes in insoluble solids level and slurry viscosity as pretreatment and enzymatic hydrolysis reactions proceed

• Initial project investigated:• Viscosity of biomass slurries

• CFD modeling of pretreatment reactors and stirred tank bioreactors

• Detoxification of pretreatment hydrolyzates (activated carbon)

• Current project focusing on:• High solids enzymatic processing strategies

• CFD simulations of pretreatment/hydrolysis reactors

• Measurement of changes in rheological properties

Rheology and CFD Modeling—Univ. Louisville

CFD Simulations of Stirred Tank Bioreactor at Different Scales

CFD Simulations of High Solids Pretreatment Reactor (Varying Screw

Conveyor Design)

Interrupted Flight Conveyor

Conical Bottom-Lift Conveyor

Interim Stage Gate Overview

• Most Recent Review:• Pretreatment Core R&D Stage Gate Review

• June 9-10, 2005 (Golden, CO)

• Other Recent Relevant Reviews:

• May 2003 “Advanced Pretreatment” Interim Stage A Review

• May 2003 “Enzyme Sugar Platform” Interim Stage B Review

• November 2003 Office of the Biomass Program Peer Review

• May 2004 “Fundamentals and New Concepts” Interim Stage A Review

• September 2004 “Sugar Processing Integration” Interim Stage B Review

Interim Stage Gate Overview

• Pretreatment Core R&D Stage Gate Review• Covered all 8 FY05 projects in Pretreatment Core R&D Area

• June 9-10, 2005 (Golden, CO)• Reviewers:

• Academia• Sharon Shoemaker – UC Davis• Michael Penner – Oregon State University

• Industry• Bob Wooley – Nature Works• Pat Smith – Dow

• Government (DOE)• Amy Miranda – Biomass Program (HQ)• Andy Trenka – Biomass Program Project Management Center (Golden)• David Thomassen – Office of Science (HQ)

Reviewer Comments—Overall Assessment

Strengths• “Goals are relevant, realistic and well managed with stage gate disciplines.”• “Focus on critical issues/challenges. Use of merit-based research. Strong sense of

team approach to problem solving.”• “Great researchers, dedicated. Great facilities.”

Weaknesses• “Too few resources due to too little funding. DOE is not aggressive enough to

terminate projects that don’t meet milestones.”• “Funding inadequate. Not clear that major pilot scheduled for FY08 (?) will have an

adequate knowledge base from basic R&D to have the desired impact or to contribute the desired progress.”

Suggested additions/deletions to improve the portfolio • “Collaborations for the surface characterization group with academics (to come up to

speed fast) would be valuable.”• “Collaborations with knowledgeable groups on the surface characterization lab. Great

facility, eager learners and smart people at NREL, but there are experience knowledgeable people elsewhere too, who would love to help.”

Reviewer Comments—Specific Projects

• Detailed, specific comments were provided to all 8 projects in the Pretreatment Core R&D area

• Will soon be available at http://www.eere.energy.gov/biomass/progs/biogeneral/obp_gate/pehindex.html

• Specific recommendation to focus on three key areas:• Surface characterization

• High solids enzymatic saccharification

• Pretreatment and saccharification across feedstock categories

DOE Response

• Final review panel report from June, 2005 Pretreatment Core R&D Interim Stage Gate Review recently received• 45 pages, with scoring and specific comments on all 8 projects

• DOE response to reviewer comments is now underway

• Plan to have an official response document completed in January, 2006

• FY06 AOP has been drafted with consideration to initial review panel feedback• A more focused plan in FY06:

• Surface characterization• High solids enzyme saccharification• Pretreatment and saccharification across feedstock categories

Summary and Future Work

Two projects completed in FY05 (no further work in FY06)• Forest Biorefinery—Hemicellulose Extraction (as core

R&D activity)• Enzyme Subcontract Liaison

FY06 Activities on Specific Projects• Bridge to Corn Ethanol Project (Purdue/Aventine)

• Complete pilot testing of system with modified heat exchanger design

• Exploratory Saccharification Subtask • Surface characterization: Evaluate lignin re-arrangement effects across

different pretreatment approaches (CAFI, Feedstock Qualification, also Processing Integration Task samples)

• Enzyme augmentation studies: Effect of specific non-cellulase components on CAFI and Feedstock Qualification pretreated samples

Summary and Future Work

FY06 Activities on Specific Projects (cont.)• Integrate Leading Biomass Pretreatments (CAFI 2 Project)

• Pretreatment and saccharification studies on poplar feedstock• Complete development of updated process economic models

• Feedstock Qualification • Complete pretreatment pH and severity screening study of two feedstocks

(switchgrass, wheat straw)—ties to FY06 Joule milestone• 3rd feedstock in FY07 (representative forest residue)

• Enzymatic Hydrolysis• Continue to develop high solids saccharification (includes advancing

rheology and reactor design studies)• Test advanced cellulase preparations under process relevant conditions

(high solids, background sugars, hydrolyzate inhibitors)

• Rheology and CFD Modeling Project (Univ. Louisville)• CFD simulations of high solids pretreatment and saccharification reactor

designs