www.cranfield.ac.uk

Enzymatic hydrolysis: a forgotten step in AD

Dr Raffaella Villa

September 2017

2

Engineer out the step to increase the

overall rate

Pre-treatments

3

Enzymatic pre-treatment

4

What are enzymes? And how do they work?

Biological catalysts

• Reduce activation energy of reactions

• Specific• Stable and work in mild conditions

5

Advantages of enzymes

Energy Saving – mild conditions

Cost Saving – less chemicals

Cost saving – low CAPEX

Eco-friendly – biodegradable

High Specificity

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Share of enzymes use in the industrial sector

Animal feed

Food and Beverages

Paper and textile

Medicine and

Biotech

Household care

Biofuel

http://www.kyrobio.eu/index.html

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SugarsProteins

Different pre-treatments = release of differentcompounds

sCOD

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Enzymes for biogas production

Pre-treatmentDirect addition

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Cellulases: not all the same

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

1 2 3 4

Incr

eas

e in

sC

OD

(m

g/l

)

Enzyme dose (U/g TS)

100

300

600

800

1500

3000

3000

9000

9000

18000

18000

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Biogas & methane increase

Enzymes for improved biogas production, Čermáková, A., Bajón Fernández,Y. and Villa, R. in preparation

0.0 1.0 2.0 3.0 4.0

Direct addition

Pre-treatment at50°C

with enzyme

Pre-treatment at50°C

Pre-treatment at37°C

with enzyme

Pre-treatment at37°C

Biogas and methane (Nm3/kg)

Increase in Methane Production (Nm3 CH4/kg of VSadded)

Increase in Biogas Production (Nm3/kg of VSadded)

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Different enzymes = different specificity

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Biogas and methane: different enzymes

13

Different enzymes on food waste

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Direct addition of enzymes

15

Extracellular hydrolytic enzymes

16

Extracellular hydrolytic enzymes

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What’s next?

• Long term effect of enzymes at pilot scale

• Variation of HEE

• Tailoring from digestate

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Thank you for your attention

Thanks also to our funders and my co-workers on the project

Dr Yadira Bajón Fernández Jana Jantova Patel

www.cranfield.ac.uk

T: +44 (0)1234 750111T: +44 (0)1234 758363

Dr Raffaella Villa

r.villa@cranfield.ac.uk