Challenges of EthanLignocellulos

Maha

nol Production from sic Biomass

Dakar

Varieties of Ca

Sugar StarchSugar Starch

arbohydratesy

h Cellulose/Hemicelluloseh Cellulose/Hemicellulose

What All Plants H

Cellulose Gluco

Why is it difficult to hydbi i tbiomass into sugar

Have in Common

ose

drolyze lignocellulosic t k th l?r to make ethanol?

Lignocellulosic• Biomass: biological material derive

for energy related to plantgy p

• Lignocellulosic biomass: cellulosecarbohydrates) & lignin

• Cellulose: structural material in plaearth

• Lignocellulose: strength, resistanc

• Cellulose & hemicellulose: polymep yfermentable sugars

• Lignocellulosic biomass do not dir

c Biomassed from living organisms. Biomass

e, hemicellulose (complex

ants & most abundant biomass in

ce to degradation

ers of sugars, potential source of g p

rectly go into food

Lignocellulosic Bio• Woody Biomass

F t id- Forest residues- Wood waste

• Non Woody Biomass• Non-Woody Biomass- Agricultural Residues:

St ( h t b l iStraws (wheat, barley, riBagasse (sugarcane, swStover (corn milo)Stover (corn, milo)

• Organic WasteAnimal waste- Animal waste

- Sewage sludge

omass Feedstock

)ce)weet sorghum)

What is Lignocell

lignocellulose = lignin + cel

Cellulose

Hemicellulose

Ligning

ulosic Material?

llulose + hemicellulose

Composition of LLignocellulose

1st Generation vs

1st2nd

s. 2nd Generation

1st2nd

How Do We G

This ToThis To

Switchgrass Bagasse

Go From

This? This?

Plants Ce

Plants Cell Walls:- Middle lamella: pectin- Middle lamella: pectin- Primary cell wall: cellulose, hem- Secondary cell wall: lignin

Middle lamella

Primary ceSecondary cell

O ti i i l t bi f ffi i t

Secondary cellPlasma membran

Optimizing plant biomass for efficientof plant cell wall stru

ell Walls

icellulose

ell walll wall

t i i d t di

l wallne

t processing requires understanding ucture and function

Primary CPrimary C

Cellulose micPlasma memb

HemicelluloseHemicellulose

Cell WallCell Wall

rofibrilbrane

Cellulose, HemicCCompo

Very high energy content(Phenolic monomers)

cellulose, Lignin itiosition

(C-5, C-6, uronic acid, acetyl derivatives)

What We Know AIntrachhydroghydrogbond

Interchahydrogebond

About Cellulose ?hain gengen

Intersheet hydrogen bond

ainen

What We Know A

1- Cellulose fibers

2- Macrofibril

33-

4- Chains ofCelluloseCellulosemolecules

About Cellulose…

Mi fib il- Microfibril

What We Know A

Lignin Cellulose

Amorphous regions

Crystalline

Celluloscrystalline regions (blue)

BlueCrystalline regions 3

Hemicellulose

About Cellulose…

se consists of:) & amorphous/disordered regions (red)e : Red : 1

How An Engineer C

=

Can Visualize This?

Starch vs. CStarch

Monomer: glucoseLinkage: α(1-4)(1-6)Dimer sugar: maltoseUsed for: storageEnzyme Hydrolysis: fastBranch: branchedChains: coiled/branched (bend)Result: granules

CelluloseCelluloseglucoseβ(1-4)

cellobiosestructural (support)

very slowunbranched

extended (rigid)long fibers

Ethanol Productio

Starch Conversion

(cook/hydrolysis)

Cellulose Conversion

(hydrolysis)

Lingocellulose

Pretreatment

on Flowchart

Grain (starch) Process

Lignocellulose Process

Cane (Sugar) Process

Grain (starch) Process

FermentationSugar Distillation

BIOETHBIOETHBIOETHBIOETHSUGAR STARCSUGAR STARCSUGAR STARCSUGAR STARC

HANOLHANOLHANOLHANOLCH CELLULOSECH CELLULOSECH CELLULOSECH CELLULOSE

Steps of Biomas

1 2 31 2 3

Milling Cooking Liquef

Gra

ins

ss Processingg

3 4 53 4 5

Ethanol

SSF Distillationfaction

Ethanol

1-Crush

• Size reduction: milling or chig• Accessibility for pre-treatme

hingg

ippingpp gnt step

ObstaclC ll tiCollection:- Type/sequence of collection operat

E i t l t i ti ( t l- Environmental restrictions (control

Transportation:Distance from plant & biomass amo- Distance from plant & biomass amo

- Bulky in nature

- Increase density by chipping, grind

Storage:Storage:- Hauled to plant

- Stored at production sitep

les tions & equipment efficiency

l i il d ti it b l l)l erosion, soil productivity, carbon level)

ountount

ding or shredding

2- Pre-TreaThe main purpose for pretreatm- Destroy lignin shell protecting celluy g p g

- Decrease crystallinity of cellulose

- Increase porosity

- Must break this shell for enzyme toMust break this shell for enzyme toaccess substrate (sugar) A

r

Pre-Treatment methods:- Chemical- Physicaly- Biological

atmentment:

ulose and hemicellulose

oo Amorphous region

Crystalline region

Chemical Prre-Treatmet

Physical Prey e-Treatment

Biological Pre-Biological Pre

fungi

-TreatmentTreatment

Obsta• Most expensive stage in 2nd

• Inhibitors such as:- Phenolic from lignin degra- Furfural from C-5 degradat- Furfural from C-5 degradat- HMF from C-6 degradation

C i bl• Corrosion problems

• Acid recovery is expensivey p

• Material loss

• Better understanding of plan

aclesgeneration bioethanol

adationtiontion

n

nt cell wall structure & function

3- HydroyPolysaccharides break down infermentation and distillationfermentation and distillation

Cellulose can be hydrolyzed usAcid hydrolysis (Traditional method)- Acid hydrolysis (Traditional method)

- Enzymatic hydrolysis (The current stat

Acid hydrolysis advantages:Acid hydrolysis advantages:- Faster acting reaction- Less residence time in reactor

Enzymatic hydrolysis advantag- Run at lower temperature- Higher conversion

Environmentally friendly- Environmentally friendly

olysisynto monomers followed by

sing:

te-of-art method)

ges:

3- Hydro

• Cellulase enzyme depolymerize cCellulase enzyme depolymerize c

• Cellulase synthesized by fungi any y gdegrade cellulose

• Cellulosic enzyme system:1- Endo-ß-glucanase2 E ß l2- Exo-ß-glucanase3- ß-glucosidase

olysis…

cellulose into fermentable sugarscellulose into fermentable sugars

nd bacteria work together to g

From Cellulose

Reaction Pathway:

O ti P tOptimum Parameters:pH: 4-5Tempt: 40-50CpInhibitors: glucose, cellobiose

e to Glucose

, some minerals

Obstac• Problems for industrial application:

1- High production cost (~40% o2 Low yield2- Low yield

• Few microorganisms are capable of

• Trichoderma produces endo-ß-glucaß-glucosidase

• Aspergillus produces endo-ß-glucanexo-ß- glucanase

• Inhibitors formation• Inhibitors formation

• Optimizing/understanding enzymes

• Understanding of plant cell wall stru

cles

of total )

f degrading cellulose

anase, exo-ß-glucanase & low levels of

nase, ß-glucosidase & low levels of

regulation and activity

ucture & function

4- Fermen

• Convert sugars (C 5 and or C 6) to• Convert sugars (C-5 and or C-6) to

• S.cerevisie for ethanol from glucos

• S.cerevisie not able to ferment (C-5

• Some bacteria ferment C-5 & C-6 (E

ntation

ethanol using microbesethanol using microbes

se (C-6)

5)

E.coli & Z.mobilis)

Obsta• Inhibitors such as:

- Phenolic from lignin deg- Furfural from C-5 degrad- HMF from C-6 degradati

• R&D strategies:- Robust organism to ferm

Robust organism toward- Robust organism toward

• Integrate hydrolysis and ferme

• Low conversion rates for C-5 s

• Technology to remove inhibito

acles

gradationdationon

menting C-5 & C-6d inhibitors/temperatured inhibitors/temperature

entation into a single microbe

sugars

ors is expensive

After All TheseCellulose HydrolyCellulose Hydroly

Hemicel

e Challenges In ysis What Aboutysis, What About llulose?

HemiceluHemicelu

Polysaccharides that arthan sugar and less comthan sugar and less com

Th d b d tThe second abundant reearth after cellulose

ulloseullose

re more complexmplex than cellulosemplex than cellulose

bl bi ienewable biomass in

Hemicellulose vHemicellulose

Polysaccharides: hetro-polysaccharPolysaccharides: hetro-polysaccharMonomer: different sugar mon

(xylose, glucose, mannose, galactA id H d l i f tAcid Hydrolysis: fastBranch: branchedDP: 150-200Structure: amorphous

vs CelluloseCellulose

rides homo-polysaccharidesrides homo-polysaccharidesnomers same monomertose, uronic acid) (glucose)

lslowunbranched800-17000crystalline

Bagasse Chag aracteristics

Brazil S

ExtractionCane Bagass

Sugar Cane

Ethanol SteamEthanolPlant

Electric

Strategy

eBoiler

Steam

mGenerator

city Electricity Grid

BagasseBagasse Pulp and Paper Mill

Bagasse

NaOHDigesterg

SuspendedSuspendedPulp Liquor

Pulp/paper

e Usage

Boiler

Steam ElectricityElectricityGrid

Bagasse g

Bagasse

Steam

H SODigester

H2SO4

Sludge

Boiler

Usage…g

Furfural(Vapor)(Vapor)

Bagasse

WateBagasse

g

H2SO4H2SO4 Digester Separa

C

BoileBoile

Usage…

er

g

C5C5

C5

ator Neutralization

CO2C6, Lignin Fermentation

Ethanoler t a oer

Bagasse

WBagasse

g

Steam

H2SO4 Digester Se

Enzymes

Boiler FermLignin

Boiler Ferm

Usage…

Water

g

C5

CO2

C5

C5

eparator Neutralization

CO2

C6, LigninFermentation

CO

Ethanolmentation

Extra Ethanol

CO2

t a omentation

Brazil Str

Cane BCane

Sugar Juice

BagasExtraction

Sugar Juice

EthanolPlant Neutral

ExtraC5

EthanolExtra Ethanol Fermen

rategyH SOH2SO4

sseDigester

WaterC5 Separatorlization

CO2 LigninC6

Boilerntation

Where is KATZE

KATZEN has worked with cellulKATZEN has worked with cellulpulp and paper & sulfite liquor

After this long history, we say Cethanol feedstock but limited to

After this long history we say YAfter this long history, we say Y

EN From This?

lose feedstock for ethanollose feedstock for ethanol, over 50 years

C6 will have contribution as o special circumstances

YES for C5YES for C5