CoER : Biofuels Department of Microbiology • Faculty of Natural Sciences

UNIVERSITEIT • STELLENBOSCH • UNIVERSITY

jou kennisvennoot • your knowledge partner

Production of biofuels from

cellulosic industrial waste streams

WH (Emile) Van Zyl & Johann F Görgens

Department of Microbiology, University of Stellenbosch,

Private Bag X1, Matieland 7602, South Africa

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CoER : Biofuels (members)

Microbiology

Chem Eng Proc Eng

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Lignocellulose composition

Sugarcane bagasse Lignin 28%

Arabinan 2%

Xylan 25%

Cellulose 46%

Hexoses (fermentable) Pentoses

(fermentable)

Non-fermentable sugars

high energy aromatics

Technologies for Cellulose Conversion

Thermo-

chemical

routes

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Lignocellulose

feedstock or

residue

Pyrolysis Pyrolysis

oils

Charcoal

Transportation

fuels

Catalytic

Upgrading Refining

Gasification

Product gas

or syngas

Syngas

Combustion for

heat/electricity

Product

gas

Synthesis Refining

Pretreatment Enzymatic

hydrolysis

Fermentation

to ethanol Distillation

Biological route

to cellulosic

ethanol

Cellulosic

ethanol

Residues for

thermo-chemical

conversion

Consolidated BioProcessing

Combustion

in boiler

High

pressure

steam

Surplus heat

Steam

turbine Electricity Biogas

Cooking fuel

Lignocellulosic Biomass Conversion Options

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Microbial conversion of cellulose to ethanol

Sustainable Biofuels

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Ethanol production from cellulosics

Enzymatic hydrolysis of biomass

Ligninases (laccases, lignin peroxidases, Mn-peroxidases)

Cellulases (endoglucanases, cellobiohydrolases, -glucosidases)

Hemicellulases (xylanases,-xylosidases -arabinofuranosidases -glucuronidases)

Esterases (feruloyl esterases, coumaroyl esterases)

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Ethanol production from cellulosics

Spent

material

Pre-treatment

Chipping

Grinding

Agric Res

Woody

Material

Grasses

Water

mixing

tank

Steam explosion

~200ºC

Cellulases

Fuel

blending

Saccharification

Alcohol recovery

Distillation & dehydration

Storage

tank

Yeast

Fermentation

Technologies for Ethanol Production

Steamgun Pretreatment of Lignocellulose

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Consolidated BioProcessing (CBP)

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Pre-treatment

Cooling &

conditioning

Chipping

Grinding

Agric Res

Woody

Material

Grasses

Water

mixing

tank

Steam explosion

~200ºC

Cellulases

Saccharification

Yeast

Fermentation

Ethanol production from cellulosics

Spent

material

Fuel

blending

Alcohol recovery

Distillation & dehydration

Storage

tank

Cellulolytic Yeast

Saccharification & Fermentation

Ethanol production from cellulosics

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Spent

material

Fuel

blending

Alcohol recovery

Distillation & dehydration

Storage

tank

Pre-treatment

Cooling &

conditioning

Chipping

Grinding

Agric Res

Woody

Material

Grasses

Water

mixing

tank

Steam explosion

~200ºC

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Xylose utilization by yeast

Recombinant S. cerevisiae

G-6-P

F-6-P

F-1,6-dP

DHAP

Glycerol-3-P

Glycerol

G-3-P

1,3-dP-Glyc

3-P-Glyc

2-P-Glyc PEP PYR

Ethanol

Acet

Acetic acid

E-4-P

S-7-P

Xylul-5-P

Xylulose

Glucose

Ribul-5-P 6-P-Gluc 6-P-Gluclac

Rib-5-P

NADH + H+ + ½O2 + 3ADP + 3Pi

NAD+ + H2O + 3ATP

MITOCHONDRION

ATP

ADP

NADPH NADP+ NADPH NADP+

CO2

ADP

ATP

NAD+

NADH NAD+

NADH

ADP

ATP

NAD+

NADH

Pi

XK

RPE

RKI

TKL

TKL

TAL

PGI

HXK

GPD

ENO PYK PDC

ALD

NAD(P)+

NAD(P)H

CYTOSOL

Glucose

ADP

ATP

Xylose

Xylitol NAD+

NADH

XR

XDH

Xylose

NAD(P)H

NAD(P)+

ADP ATP CO2c

GPDH

PGDH

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Recombinant S. cerevisiae

G-6-P

F-6-P

F-1,6-dP

DHAP

Glycerol-3-P

Glycerol

G-3-P

1,3-dP-Glyc

3-P-Glyc

2-P-Glyc PEP PYR

Ethanol

Acet

Acetic acid

E-4-P

S-7-P

Xylul-5-P

Xylulose

Glucose

Ribul-5-P 6-P-Gluc 6-P-Gluclac

Rib-5-P

NADH + H+ + ½O2 + 3ADP + 3Pi

NAD+ + H2O + 3ATP

MITOCHONDRION

ATP

ADP

NADPH NADP+ NADPH NADP+

CO2

ADP

ATP

NAD+

NADH NAD+

NADH

ADP

ATP

NAD+

NADH

Pi

XK

RPE

RKI

TKL

TKL

TAL

PGI

HXK

GPD

ENO PYK PDC

ALD

NAD(P)+

NAD(P)H

CYTOSOL

Glucose

ADP

ATP

Xylose

Xylitol NAD+

NADH

XR

XDH

Xylose

NAD(P)H

NAD(P)+

ADP ATP CO2c

GPDH

PGDH

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xylose fermentation to ethanol

My laboratory, in collaboration with Barbel Hahn-Hägerdal in Sweden,

were one of the first to develop a xylose-fermenting yeast (TMB3400),

today several are available. 15

Recombinant S. cerevisiae

G-6-P

F-6-P

F-1,6-dP

DHAP

Glycerol-3-P

Glycerol

G-3-P

1,3-dP-Glyc

3-P-Glyc

2-P-Glyc PEP PYR

Ethanol

Acet

Acetic acid

E-4-P

S-7-P

Xylul-5-P

Xylulose

Glucose

Ribul-5-P 6-P-Gluc 6-P-Gluclac

Rib-5-P

NADH + H+ + ½O2 + 3ADP + 3Pi

NAD+ + H2O + 3ATP

MITOCHONDRION

ATP

ADP

NADPH NADP+ NADPH NADP+

CO2

ADP

ATP

NAD+

NADH NAD+

NADH

ADP

ATP

NAD+

NADH

Pi

XK

RPE

RKI

TKL

TKL

TAL

PGI

HXK

GPD

ENO PYK PDC

ALD

NAD(P)+

NAD(P)H

CYTOSOL

Glucose

ADP

ATP

Xylose

XI

Xylose

ADP ATP CO2c

GPDH

PGDH

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Expression of cellulases in yeast

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Consolidated BioProcessing (CBP)

O O

O

O

O

Glu Man Gal

Xyl Ara

Ethanol + CO2

P T YFG

Glycosyl

Hydrolases

Technologies for Cellulose Conversion

Van Zyl et al. 2007. Adv. Biochem. Eng./Biotechnol. 108:205–235

La Grange et al. 2010. Appl. Microbiol. Biotechnol 87:1195–1208

Lynd et al. 2002. Microbiol. Mol. Biol. Rev. 66:506–577

Lynd et al. 2005. Curr. Opin. Biotechnol. 16:577–583

Background strain

Appearance at 120 hrs.

CBP strain

0

10

20

30

40

50

60

0 50 100

Eth

ano

l co

ncent

ration

, g/

L

Time (hours)

CBP + 1 mg Xylanase

Background +BGL + Xylanase

Background + Cellulase + BGL + Xylanase

Mascoma CBP technology on 18% w/w paper sludge

Enzyme Reduction on Paper Sludge

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Converting Paper Sludge to Cellulosic Ethanol and Biogas

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The problem

Paper sludge is waste from paper production and recycling

Contains degraded cellulose fibres

15 to 50 dry tons per day per site going to landfill

Landfill costs are high

Environmental impact

Limits landfill space Reduce Water to landfill (+60% moisture) Reduce methane release at landfill

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The solution

Transform waste into green transport fuel Mitigate environmental impacts with

attractive returns

Convert paper sludge to bio-ethanol with CBP Avoid high enzyme costs (critical for

viability) Reduce waste to landfill (50%) (GHG, space) Reduce water content and water to landfill Does not impact on food production Ethanol is a green replacement for fossil fuel

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The Paper sludge Pilot

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The Financial Summary

Dependent on

Equipment cost Paper sludge cost Ash content of

sludge Production scale

Selling price of

ethanol

Assumptions

ZAR 65m (ZAR880/ton) 10%

50 dry tons per day 5.4 ML/annum EtOH ZAR5 – 7 per litre

Returns

NPV = ZAR 26.8m Project IRR = 27% Payback = 3 years Viable with 50%

reductions

For more information, contact : Johann Görgens -

jgorgens@sun.ac.za Mobile: +27 82 448 4648

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• Feedstock:

• Ngodwana Raw

• Virgin Paper Mill Sludge

• Springs Raw

• Recycled Paper Mill Sludge

• Springs Processed

• Residues from ethanol fermentation of Raw Springs

• Inoculum:

• Mesophilic mixed culture sourced from SAB’s Newlands Brewery Anaerobic Digester

Production of biogas from paper sludge

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Effect of Solids Loading & pH on Biogas Production

0

20

40

60

80

100

120

6% 10% 14% 6% 10% 14% 6% 10% 14% Ngodwana Raw Springs Raw Springs Processed

Trends in biogas production as a function of solids

loading

(kg

Bio

gas/

ton D

ry F

eed

0

20

40

60

80

100

120

6 7 8 6 7 8 Springs Raw Springs Processed

Trends in biogas production as a function of pH

(kg

Bio

gas/

ton D

ry F

eed

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Combined ethanol and Biogas production

• Viability of Combined Ethanol and Biogas Production

• Production of Processed sludge generally lower than the raw sludge, however the processed sludge shows promise at higher solids loading – add value to ethanol production

• Difference between maximum biogas production for processed and unprocessed sludge small

• Water Recovery

• Marginally poorer performance for processed sludges, but benefits need to be considered

• Use as composting material

• All the samples give promising results with C:N ratios lying between 9 and 15 – will provide high nitrogen feedstock

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Evolutionary deploying of 2nd Gen Technology

1

10

100

1000

Cap

ital

Co

st –

ZA

R (

mill

ion

)

Time

Paper Sludge

Mobile pilot

Onsite ethanol 1

Commercial xylose

40 ML pa

Revenue: ZAR220m pa 3

Biorefinery

160 ML pa + electr

Revenue: ZAR880m pa

4

Commercial paper sludge

5 ML pa

Revenue: ZAR30m pa 2

Utilize xylose-rich waste streams

• Xylose waste streams from Sappi Saiccor (Durban) (SSL = Spent Sulphite liquor) and hemisellulose waste streams from the cooking process at the Ngodwana mill (Nelspruit)

• Can be fermented by the new generation xylose fermenting yeast that have been hardened for inhibitors. This could produce 100ML/an ethanol and can be demonstrated with the same mobile pilot unit.

• Furthermore, as a first step towards integration of 1st Gen and 2nd Gen technologies in, for example the sugar industry, xylose can be extracted from bagasse and sugercane straw through mild pretreatment and fermented to ethanol, whereafter the remainder can be used for heat or electricity production.

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Sustainable biofuel production in Africa

Thank you!