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Wood ChemistryPSE 406

Bioenergy-Hydrolysis

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Agenda

Enzymatic hydrolysis» Cellulases» Experimental

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Biomass

Pretreatment

Liquid phase

Solid phase

Cellulose

Sugars EthanolFermentation

Ethanol SugarsFermentation

Hydrolysis

LigninRecovery

Bioconversion of biomass to ethanol (hydrolysis)

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Enzyme Function There are a large number of fungal enzymes

responsible for the breakdown of each wood component. Each enzyme plays specific roles:» Endo-beta-1,4-glucanase acts within the chain,

breaking it into smaller units and providing more "ends" for CBH.

» Cellobiohydrolase (CBH), acts on the end of the molecule successively cleaving off the disaccharide cellobiose.

» Beta-glucosidase (or cellobiase) which cleaves cellobiose to two glucose units.

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Trichoderma reesei

Trichoderma reesei is an industrially important cellulolytic filamentous fungus.

T. reesei:» present in nearly all

soils and other diverse habitats

» favored by the presence of high levels of plant roots.

Trichoderma reesei

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Cellulases

Endoglucanases  (EG) cutting the cellulose chains randomly

Cellobiohydrolyses (CBH) cutting cellobiose units of the ends of the cellulose chains

Binding domain Catalytic domain

7 Pretreated substrate Handsheet Microplate

“Rapid microassay method (1)”

Pretreated substrate Flasks

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“Rapid microassay method (2)”

Handsheets

Microplate

Shaker

MicroplateReader

HPLC

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“Rapid microassay method (3)”

Advantages over the flask based method:» Faster processing time (10x)» Cheaper (enzyme and

substrate requirements 200x)

» Efficient (768 versus 30 samples)

» Smaller lab area required (30x)

Equipment and development cost (<$3,000)

Berlin, A., Bura, R., Gilks, N., and Saddler, J.N., (2005)

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Equipment

1mL 200 mL 4L

40L

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Enzymatic hydrolysis

0 10 20 30 40 500

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40

60

80

100

C

ellu

lose

con

vers

ion

(%)

Time (hours)

corn fibre corn stover poplar