2005 OBP Biennial Peer Review

1
2005 OBP Biennial Peer Review

• Pretreatment Enzymatic Hydrolysis
• Rick Elander (NREL)
• Biochemical Conversion Platform
• November 15, 2005

2
Work Breakdown Structure
3
Platform Fit with Pathways
4
Barriers
Commercial Success Barriers Price of Sugars from
Cellulosic Biomass
Major General Barriers Feedstock Cost Sugars
Composition Sugars Yield Conversion Rate Sugars
Quality Capital Investment
RD Technical Barriers Feedstock-Sugars
Interface Biomass Pretreatment Enzymatic
Hydrolysis Sugars Processing Process Integration

• Biomass Recalcitrance
• New Pathways
• Enabling Tools

5
Overview
Budget (FY05)
Partners

• NREL (Pretreatment and Enzymatic Hydrolysis Task)
• Aventine/Purdue University
• CAFI Universities
• Auburn University
• Dartmouth College
• Michigan State University
• Purdue University
• Texas AM University
• University of British Columbia
• Neoterics Intl.
• Harris Group Inc.
• Novozymes
• Genencor Intl.
• Merrick Co.
• University of Louisville

6
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 Enzymatic Hydrolysis
2.3. Processing Integration
2.4. Targeted Conversion Research
7
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)

8
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

9
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

10
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 RD 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

11
Forest Biorefinery--Hemicellulose Extraction

• 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 USDAs Forest
  Product Lab to evaluate pulp quality

Recirculating Chip Extractor
12
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)

13
Exploratory (Pretreatment) Saccharification
Enzyme Augmentation Studies on ARP (CAFI)
Pretreated Corn Stover
Surface Ultrastructure Changes Upon Dilute Acid
Pretreatment
Corn stem xylem No pretreatment
Corn stem xylem 1.5 H2SO4,150oC, 20 min
14
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)

15
Feedstock Qualification
Initial Findings on Switchgrass Across Wide pH
Range

• Standard methodology for pretreatment and
  enzymatic saccharification developed
• Initial data on switchgrass generated

MultiClave 10-Well Reactor
Sand Baths for Reactor Heating

16
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 RD in the Exploratory
  Saccharification and Plant Cell Wall
  Deconstruction subtasks

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Integration of Leading Biomass Pretreatments
(CAFI 2)
Comparative Sugar Yields and Process Economics
from CAFI 1 Data
AFEX
1.75
Dilute Acid
Hot Water
ARP
Lime
Flow-through
1.50
MESP, /gal EtOH
1.25
1.00
Dilute Acid
Hot Water
AFEX
ARP
Lime
w/o Oligomer Credit
w/ Oligomer Credit
Initial Findings from CAFI 2 Project

• 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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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

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Enzyme Subcontract Liaison
Pretreated Corn Stover (PCS) Substrate
Improvements
Improved Enzyme Preparation on Pretreated Corn
Stover (PCS)
100
100
90
90
80
80
70
70
Cellulose Conversion
60
60
50
Cellulose Conversion
50
40
Benchmark prep
Improved PCS
40
30
Improved prep
30
Original PCS
20
Benchmark prep
20
Improved prep
10
10
0
0
0
10
20
30
40
50
60
70
0
10
20
30
40
50
60
70
Soluble Protein Loading (mg protein/g cellulose)
Soluble Protein Loading (mg protein/g cellulose)

• 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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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

21
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
25 solids before hydrolysis begins

22
Rheology and CFD ModelingUniv. 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

23
Rheology and CFD ModelingUniv. 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

24
Interim Stage Gate Overview

• Most Recent Review
• Pretreatment Core RD 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

25
Interim Stage Gate Overview

• Pretreatment Core RD Stage Gate Review
• Covered all 8 FY05 projects in Pretreatment Core
  RD 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)

26
Reviewer CommentsOverall 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 dont meet milestones.
• Funding inadequate. Not clear that major pilot
  scheduled for FY08 (?) will have an adequate
  knowledge base from basic RD 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.

27
Reviewer CommentsSpecific Projects

• Detailed, specific comments were provided to all
  8 projects in the Pretreatment Core RD area
• Will soon be available at http//www.eere.energy.g
  ov/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

28
DOE Response

• Final review panel report from June, 2005
  Pretreatment Core RD 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

29
Summary and Future Work

• Two projects completed in FY05 (no further work
  in FY06)
• Forest BiorefineryHemicellulose Extraction (as
  core RD 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

30
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