biofuelsproduction & environmental impacts: a european ... · 1975 1980 1985 1990 1995 2000...

Graeme Walker

BiofuelsBiofuels Production & Environmental Impacts: Production & Environmental Impacts: A European perspectiveA European perspective

www.abertay.ac.uk

Federation of Latin American Chemical Societies Meeting July, 2008

Outline

• European Biofuels: overview

• Bioethanol: pros & cons, environmental impact

• Bioethanol: current processes, future challenges & opportunities

• Bioethanol from lignocellulose

• Conclusions & future prospects

Environment

Agriculture

Fuel Security

Why biofuels?

• Biogas (Anaerobic Bacteria)

• Biodiesel (Brassica napus, Animal/veg oils)

• Bioethanol (Yeast)

• Biohydrogen (Cyanobacteria, Clostridia, PNS bacteria)

• Bio-oil (Botryococcus braunii, other microalgae)

• Biobutanol (C.butylicum, C.acetobutylicum)

European BiofuelsThe 20:20 goal = 20% renewables by 2020

Current production

Research & Development

Biodiesel in Europe

• Biodiesel accounts for 76% of total biofuelconsumed in the EU

• EU biodiesel production set to increase by 55% in 2008 to 16Mt (European Biodiesel Board)

• But, in 6 EU countries, biodiesel production has fallen since 2006 (due to higher feedstock prices and subsidised imports from USA)

Projected Fuel Ethanol Consumption. Source: IEA

0

20000

40000

60000

80000

100000

120000

140000

1975 1980 1985 1990 1995 2000 2005 2010 2015 2020

Year

Mill

ion

Litre

s

Brazil US & Canada EU World

Bioethanol: Global Consumption[Note: All Biofuels expected to account for 8.5% of global energy use by 2030

– US Energy Information Administration]

European bioethanol?

Substrates:- Sugarbeet

- Wheat

0

50

100

150

200

250

300

350

400

Country

SpainGermanyFrancePolandItalySwedenHungaryLithuaniaCzech RHolandLatvia

millionL2006

Biofuels in the UK(HGCA Newsletter 2/4/08)

• So far, UK biofuel production is much less than the amount required to fulfil the RTFO target (5% by 2010) • Currently biofuels only account for a small percentage of the UK fuel market, a mere 0.70%.• There is presently only one ethanol plant in operation (British Sugar, production capacity of 55,000t).• This would suggest that total UK biofuel production for 2007 was around a quarter of a million tonnes.

British bioethanol (1936)

Why Bioethanol?

Pros ConsCO2 neutral Food-to-fuelReduced dependence on oil Lower oil priceAgricultural diversification SustainabilityClean burning, low toxicity Energy balanceLess GHG emissions (~65% less) Residues, emissionsHigher flash points (better fire safety) Inefficient microbesBetter biodegradability Hydroscopic Co-generation of electricity Less mpg

[Climate saviour or climate pariah?]

Bioethanol:current substrates?

Brazilian ethanol programme (Proalcool*)

SUGAR CANE

Bagasse Ethanol Sugar CO2 Fusel oil Vinasse Yeast

Animal feed, Fuel Food Chemicals Biogas Animal feedelectricity

*~380 Distilleries in Brazil>24bn litres ethanol/yr

[40% of transport fuel]

>700,000 jobs created>$2bn savings pa.

USA Bioethanol processes (Gasahol)

CORN (maize)

Crude starch

Syrup conversion

Fermentation

Distillation

GASAHOL

Microbial amylases

Yeast

By the end of 2007, U.S. will have processed 3 bn bushels of corn for

ethanol = 30.28 billion liters

Bioethanol

Scientific & technological challenges(especially from lignocellulosic feedstocks)

NOTE: lignocellulosic ethanol production/consumptionestimated to result in 75-80% Green-House-Gas emissions reduction compared with gasoline

Second-generation bioethanol:some potential cellulosic (non-food) feedstocks

• Wood chips/sawdust/forestry residues/SRC

• Waste paper

• Corn fibre/cobs/stover

• Municipal Solid Waste, MSW

• Straw, bagasse

• Cereal hulls/spent grains

• “Energy crops”(Switchgrass, Miscanthus, Ryegrass, etc.)

• Cyanobacterial cellulose

Some cellulose-to-ethanol plants (USA)

• New York & Michigan (wood chips – Mascoma)

• Tennessee (switchgrass – Mascoma)

• Maine (wood chips – RSE Pulp & Chemical)

• Kentucky (corncobs – Ecofin/Alltech Inc)

• Louisiana (bagasse – Celunol)

• Ohio (corn fibre – Genahol)

Selected international others:Iogen (straw –Canada); Abengoa (straw –Spain, US); Etek (softwood –Sweden); Elsam (straw –Denmark); TMO (straw/wastepaper–UK); NEDO (rice straw –Japan); Tavda (wood –Russia); Mossi & Chistophi (sorghum fibre –Italy)

Lignocellulosic bioethanol– key areas for improvement

• Cellulose hydrolysis– Steam explosion, acids, enzymes (cellulases, arabinozylanases, ligninases)– New pre-treatments: ozonolysis+ultrasound?– SSF (e.g. Thermoanaerobacterium saccharolyticum)

• Fermentation– Xylose fermenting yeasts or bacteria– Very high gravity wort (>20%v/v ethanol)– Thermotolerant/alcohol tolerant/inhibitor tolerant yeasts– Optimised nutrition (esp. metal ions like Mg, Zn)

• Distillation– Anhydrous ethanol (molecular sieves, azeotropes, membrane pervaproation)– Energy balances!

SecondSecond--generation generation bioethanolbioethanol: research challenges: research challenges

Lignocellulosicmaterial

Pre-hydrolysis [physico-chemical]

Hydrolysis [biological]

Fermentation (hexose)

Distillation

BIOETHANOL

Pretreatment

3

2

1

4

EnergyFermentation (pentose)

Ethanologenic yeasts

Feedstock Fermentable substrate Yeasts*-Wheat, Maize, Barley Starch hydrolysate (maltose, glucose) Saccharomyces-Sugarcane/Beet Sucrose Saccharomyces

-Potato, Rice Starch hydrolysate (maltose, glucose) Saccharomyces-Agave/Artichoke Inulin hydrolysate (fructose) Kluyveromyces-Cheese whey Lactose Kluyveromyces-Raw starch Starch Schwanniomyces-Seaweed Laminarin (glucose) Pichia angophorae-Paper, sawdust, straw, Xylose, arabinose, glucose, Pichia, Candida, wood, spent grains, cellobiose Pachysolen,cornsteep liquor, paper, Kluyveromycesrapeseed residues, MSW, GMS.cerevisiaebagasse, corn fibre

*Other microbes? Zymomonas, E. coli (GM), Klebsiella (GM),Bacillus (GM), Thermoanaerobacterium saccharolyticum

Saccharomyces cerevisiae strains cannot ferment pentose sugars as D-xylose and L-

arabinose. Too bad, because…

•Grass (16% xylan, 5% arabinan)

•Corn stover (19% xylan, 3% arabinan)

•Wheat bran (19% xylan, 15% arabinan)

•Barley husks (20% xylan, 9% arabinan)

Xylose fermentation pathway

Xylose

Xylitol

Xylulose

ETHANOL

XR

XDH

Xylose isomeraseBacteria, Piromyces

S. cerevisiae

• Brettanomyces naardenensis

• Candida intermedia var intermedia

• Candida lyxosophila

• Candida shehatae var. lignosa

• Candida tenuis

• Cryptococcus albidus

• Kluyveromyces marxianus

• Pachysolen tannophilus

• Pichia stipitis

• Yeasts are extremely diverse physiologically(but yeast biodiversity virtually untapped)

• S.cerevisiae is a rather exceptional yeast and may not be the best for bioethanol (xylose non-fermenter)

• We need more knowledge of yeast cell physiology (Especially in non-Saccharomyces yeasts)

• Yeast stress is a dilemma (e.g. ethanol tolerance)

• Bacteria are competitive

The yeast message

BioethanolBioethanol from from spent grains?spent grains?

???

Whisky Production (x106 L p.a.)

Yield alcohol (L/t)

Residues

(1000 t dry matter)

Grain

(wheat or maize)

273 490 209

Malt (barley)

170 531 135

Spent grains are cereal residues from breweries

and distilleries

Lager brewery Grain distillery Ale brewery Malt distillery

100% malt85% malt 15% wheat

86% maize 14% malt

96% malt4% roasted

malt

Scottish grain and malt distilleries

2006 figures

Bioethanol from spent grain: Current Research

Pre-hydrolysis

Enzyme Hydrolysis

Distillation

BIOETHANOL

Pretreatment

Fermentation (Glucose, xylose, arabinose)

1. Temp? Acids?

2. Novel pre-treatments?

3. Enzymes

4. Characterisation of sugars, inhibitors

−Ale (malt)

− Lager (malt + wheat)

−Whisky (malt)

−Spirit (maize + malt)

• C6 & C5 sugars

• P. stipitis,

K. marxianusetc.

“Potential” bioethanol from UK spent grains

British Breweries (2007)

• 210,974 tonnes SG

• Would yield:

21M litres bioethanol

Scottish Distilleries (2007)

• 297,000 tonnes SG

• Would yield

20.5M litres bioethanol

NOTE: Existing (lab-based) process is inefficient(hydrolysis and Pichia or Kluyveromyces fermentation ~20%CE)

- estimated potential >100M litres/year

Novel lignocellulose pre-treatment technology?

• Ultrasound (20 kHz-1 MHz)

+• Ozonolysis (O3)

O3 O2 + O .O + H2O 2HO

2HO H2O2

. ..

oxygen atom

hydroxyl radical

hydrogen peroxide

O

OO

OH

OH

O

CH2OHOOH

OH

CH2OH

O

OO

OH

OH

O

CH2OHOOH

CH2OH

O

O

OO

OHO

CH2OHOOH

OH

CH2OH

O

OO

OO

CH2OHOOH

OH

CH2OH

HO.

(1)

(1)

(2)

(2) hydroxyl radical

Conclusions & future prospects

• Global biofuels increasing rapidly

• Europe is lagging behind (esp. bioethanol in UK)

• Yeast biodiversity is untapped for fermentation

• New lignocellulosic pre-treatments required

• Plentiful biowaste available (eg. spent grains, straw, wood, corn residues, paper etc.)

• 2nd-generation bioethanol is the way forward!

Acknowledgements

• Abertay University Yeast Group

(Raffaele De Nicola, Jane White, Biju Yohannan, Stelios Logothetis, Irma

Ochigava, Paola Bruno, Jason McColm, Jason Bennett, David Bremner, Rashmi

Chand)

• Royal Society of Chemistry, FLAQS organisers

Thank you!