The Role of Catalysis in Sustainable Conversion of Biomass:

the Biocatalysis Perspective

Roger A. Sheldon

Joint Symposium PIRE-CBIRC-CatchBio

Symposium on Integration and Synergy between Biocatalysis

and Chemical Catalysis for Biorenewable Conversions

Utrecht University 16 July 2015

• Efficiently utilises (preferably renewable) raw

materials, including energy source

• Eliminates waste and avoids the use

of toxic / hazardous solvents and reagents

• In the manufacture and application of chemicals

Green (Clean) Chemistry

Sheldon, Arends and Hanefeld , Green Chemistry

and Catalysis, Wiley, New York, 2007

Anastas & Warner, Green Chemistry : Theory

& Practice ,Oxford Univ. Press,New York,1998

2

Major Sources of Waste

• Stoichiometric Reagents and Solvents

• Multistep syntheses

The Solution :

Atom and step economic catalytic

processes with low E factors

3

E = kgs waste/kgs product ideal E factor is 0

A catalyst accelerates the rate of a reaction

without being consumed

What is Sustainability?

Profit

People

Planet

4

The Three Ps

• Natural resources should be used at rates that do not

unacceptably deplete supplies over the long term

Fossil resources (coal, oil , natural gas) vs renewable biomass

• Residues should be generated at rates no higher

than can be assimilated by the natural environment

Greenhouse gas emissions (e.g. CO2) and climate change

t = 106-108 y

t = 101-102 y

The Petrochemical Carbon Cycle

sunlight

combustion

geological processes

plant biomass

CO2 photosynthesis

fuels chemicals

geological reservoirs

oil

Oil refinery

sunlight

plant

biomass

CO2 agriculture,

forestry

fuels

chemicals

combustion

Balancing the Carbon Cycle: the Circular Economy

sugars

biorefinery

www.biorefinery.nl

catalyst

catalyst

Chemo- & Biocatalysis

You can divide people into two groups.

Two Groups

7

Kenneth Boulding

(British-American

Economist & Philosopher)

Those that divide everything into two

groups and those that don’t.

The Bio-based Economy

Renewable

Biomass

Chemocatalysis

Biocatalysis

Utilising waste biomass which

doesn’t compete with food

Bioplastics

The key word is WASTE

• Rice husks: 120 X 106 tonnes / annum

• Sugar cane bagasse: 220 X 106 tonnes / annum

• Waste straw in China: 600 X 106 tonnes / annum

• Orange peel in Brazil: 8 X 106 tonnes / annum

C. O. Tuck, E. Perez, I. T. Horvath, R. A. Sheldon,

M. Poliakoff, Science, 2012, 337 , 695-699

Valorisation of Waste Biomass: the New Frontier

Ethylene Propylene Para-Xylene

150 x 106 tonnes 90 x 106 tonnes 40 x 106 tonnes

Global annual production of key petrochemicals:

Remediation -> Prevention -> Utilisation -> Valorisation

http://europeanclimate.org/wp-content/uploads/2014/02/WASTED-final.pdf

Potential for Waste Utilisation in EU

900 MT waste

(paper, food, wood),

220 MT useable in

bio-refineries.

/02/WASTED-final.pdf

16 % of transport

fuel supplied by

waste derived

biofuels by 2030

Sustainably

sourced waste can

save > 60 % GHG

emissions

http://e limate.org/w cont

~15 Billion Euro

income to rural

economy and

job creation.

Product €/ton

Average Bulk Chemical 1000

Transportation Fuel 200-400

Fermentation Feedstock 100-300

Animal Feed 70-120

Electricity Generation 60-150

Landfill -/- 400

The Valorisation Scale

11

ligno-

cellulose

Syn

gas

gasification

Pyrolysis

oil

hydrolysis

pyrolysis

lignin

+

cellulose

hemicellulose

The Lignocellulosic Biorefinery

MeOH Lower

olefins

zeolite

H2

BTX

Lower

olefins

C5 & C6

sugars

HMF FDCA

Interm

.

ZSM-5 BTX

fermentation

- EtOH

- n-BuOH

- i-BuOH

- 1,3-PDO

- 1,4-PDO

- Succinic acid

- Acrylic acid

fermentation

alcohols

diols, acids

chemocatalysis

Two Philosophies

1. Convert the biomass to ‘drop-in’ petroleum hydrocarbons

- integrated biofuel and platform chemical production

- existing petrochemical technology for further processing

2. Convert the biomass directly to platform chemicals

- redox efficiency

- for oxygenates (and nitrogenates) could be more

economical

- different economies of scale

13

The Biocatalytic Route

Pretreatment technologies:

• acid hydrolysis

• alkaline hydrolysis

• steam explosion

• ammonia fiber expansion (AFEX)

• organosolv process (EtOH)

14

Waste Ligno-

cellulose

C5 + C6

sugars

Lignin

Cellulose

Hemicellulose

pretreatment cellulase

cocktail

Biofuels

Chemicals

Bioplastics

Chemo- or

Biocatalysis

Biocatalysis is Green & Sustainable • Enzymes are derived from renewable resources and are biodegradable (even edible sometimes) • Avoids use of (and product contamination by)

scarce precious metals • Mild conditions: ambient T & P in water

• High rates & highly specific : substrate, chemo-, regio-, and enantiospecific • Higher quality product • No special equipment needed

IMPROVED YIELDS, LESS WASTE, REDUCED COSTS

er

15

Biocatalysis : why now ?

1. Genome sequencing (> 5000) (more enzymes)

2. Directed evolution technologies

(better enzymes) 3. Recombinant DNA technology

(better production) 4. Immobilization technologies (better formulation)

Lower Costs

&

Shorter Time

16

The Challenge

• Enzymes are soluble in water

• Single use is expensive

• How to reduce the enzyme costs?

Immobilization as an insoluble solid (powder)

e.g. as Cross-Linked Enzyme Aggregates (CLEAs)

But: How to separate the CLEA from a mixture with other solids?

Make the CLEA magnetic !

See: www.cleatechnologies.com 17

Heterogeneous catalyst

Cross-Linked Enzyme Aggregates (CLEAs)

• “Simple” & Broadly Applicable

• Cost-effective (no need for pure enzyme)

• Readily Scalable

Precipitation

e.g. (NH4)2SO4

or tert-butanol

18

Ferromagnetic CLEA

Enzyme in aq. buffer

Enzyme

aggregates

See: www.cleatechnologies.com

Biotechnological Conversion of Renewable Biomass to

Biofuels & Commodity Chemicals

Waste

Biomass

enzyme

Glucose

Yeast

Fermentation

e.g.

Bioethanol

• Reduce enzyme costs by recycling

• Enzyme immobilization as cross-linked enzyme aggregates (CLEAs)

• How to separate the solid CLEA from other suspended solids?

• Incorporate ferromagnetic particles in the CLEA and magnetic separation

20

“In an ideal chemical factory there is, strictly speaking,

no waste but only products. The better a real factory

makes use of its waste, the closer it gets to its ideal,

the bigger is the profit.

A. W. von Hofmann (1884)

A good company delivers excellent products and services.

A great company does all of this and strives to make the

world a better place”

William Ford Jr.

Some Final Thoughts

Thank You