biocombustiveis celulose

biocombustiveis celulose

(Parte 3 de 4)

H C o(

P P h

Alde hy de s Alcohols

Fisch er-Tr opsch

Wa xes Dies el

Ole fins Gaso line

Et ha nol o , Rh

For malde hyde Ag zeol ite s

Olefins Ga soline

MTB E Acetic Acid c a r b o n l a i o r ec t Us h o m l o g a i o

C o

Richard Bain, NREL

Steps in cellulosic ethanol production From: Breaking the Biological Barriers to Cellulosic Ethanol

The challenge is efficient conversion t/ha) yields 14.6-fold more energy than input to produce* switchgrass to ethanol calculated to consume 45% more energy than produced

Biomass

Tran spo rtOther Steam

Electricity Grin ding

Energy consumption

*Pimentel & Patzek, Nat Res Res 14,65 (2005)

Plants are mostly composed of sugars

Section of a pine board3 nm Polymerized glucose

Lignin occludes polysaccharides

Lignin Hemicellulose

Cellulose

Effect of lignin content on enzymatic recovery of sugars from Miscanthus

D Vrije et al (2002) Int J Hydrogen Energy 27,1381

Lignin

Typical grass composition cellulose

Hemi cellulose

Humphreys and Chapple, Curr

Opin Plant Biol 5,224

Lignin biosynthesis

A cleavable lignin precursor would fundamentally alter preprocessing dehydrodiconiferyl alcohol pinoresinol rosmarinic acid

Partial structure of cellulose w.doitpoms.ac.uk/tlpli b/wood/printal l.php

Possible routes to improved catalysts

• Explore the enzyme systems used by termites (and ruminants) for digesting lignocellulosic material

• Compost heaps and forest floors are poorly explored

• In vitro protein engineering of promising enzymes

• Develop synthetic organic catalysts (for polysaccharides and lignin)

Enzymatic hydrolysis of cellulose is slow Skopec, Himmel, Matthews, Brady Protein Engineering 16, 1005

Dissolution of cellulose in an ionic liquid (novel pretreatment methods may create fundamental changes)

Swatloski, Spear, Holbrey, Rogers J. Am. Chem. Soc.,124 (18), 4974 -4975, 2002

Untreated Treated

Saccharification & Fermentation Fermentation Yield Cost Impact glucose onlyadd 85% xyloseadd 85% arabinoseall other sugars 85%

Fermentation of all sugars is essential

Jeffries & Shi Adv Bioch Eng 65,118

Lignin

Typical grass composition cellulose

Hemi cellulose

Steps in cellulosic ethanol production From: Breaking the Biological Barriers to Cellulosic Ethanol

(Parte 3 de 4)

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