Hybrid biofuels

Chris SomervilleEnergy Biosciences Institute

Fate of a barrel of US petroleum

Gasoline

Diesel Fuel

Jet Fuel (Kerosene)

Propane/Propylene

NGL & LRG

Still Gas

Residual/Heavy Fuel Oil

Heating Oil

Other

Major types of components of FACE9A diesel

CRC Report FACE-1

Sources of biodiesel

CRC Report AVFL-17

Electron micrograph of a cellin an oilseed cotyledon

Triacylglycerol

4

Yield of various species varies widely

Worldwatch 2006Cellulosic(Miscanthus)

Ga

llon

s p

er A

cre

Barl

ey

Wheat

Corn

Sugar

beet

Sugar

cane

Soy

Cast

or

Sunflow

er

Rapese

ed

Jatr

opha

Palm

400

800

1200

1600

2000

0

Production numbers

• World Production– Plant lipids 127 M tonnes (36.3 bgal)

• Lubricants ($28B) 36 M tonnes– Animal lipids 22 M tonnes

Dyer et al (2008) Plant J 54,640286 gal biodiesel/tonne of lipid

Routes to potential fuels

Fortman et al, Trends Biotechnology 26,375

Lipid droplets in Candida curvata

Oleaginous yeast accumulate lipids during nitrogen limited growth

Oleaginous yeastAlgaeBacteria

Issues with diesel from microbial lipids

• Feedstock costs• 13.9 lbs sugar = 1 gal ethanol (0.67 GGE)• ~22 lbs sugar = 1 gal diesel (1.13 GGE)

• Extraction• Oxygen

• All lipid producers are aerobic

The ABE Pathway in Clostridia

Lee et al. Biotechnol. Bioeng. 101, 209

Continuous fermentation and extraction of ABE

Fuel producingorganism

Sugar

Cellfilter

Karr column(extraction)

ABE

Cell recycle

Broth recycle

Productseparation

Clean extractant

Saturated Extracant

From Ashie Bhandiwad

An example of hybrid fuels

12Toste et al, Nature 2012; Sreekuma et al ChemSusChem 7,2445

Fermentation

Sugars

H2 H2 H2

Optimization of liquid-phase catalysis in a flow system

0 50 100 150 200 250 3000

0.02

0.04

0.06

0.08

0.1

0.12

Time-on-stream (h)

ABE

con

vers

ion

From Dean Toste, Alex Bell et al

Many additional fuels can be made from biomolecules by simple chemistry

(eg. Guerbet reactions)

F. Dean Toste, Pazhamalai Anbarasan,Joseph B. BINDER, Paul A. Willems,Douglas S. Clark, Zach Baer, Sanil Sreekumar, Harvey W. Blanch, (2012) US20140137465 A1

Building large structures

Examples of products from ABE condensation chemistry

F. Dean Toste, Pazhamalai Anbarasan,Joseph B. BINDER, Paul A. Willems,Douglas S. Clark, Zach Baer, Sanil Sreekumar, Harvey W. Blanch, (2012) US20140137465 A1

Perspective

• Hybrid biofuels provide a route from sugar to jet and diesel• The ABE process was previously commercialized, can run in

continuous mode, and is promiscuous regarding feedstock• Relatively simple and robust catalysts can be used• No external hydrogen is required to produce alkanes• The process runs anaerobically at similar efficiency to ethanol

(on an energy basis)