Food, Feedstocks and Ethanol Production

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Food, Feedstocks and Ethanol Production

• Michael H. Penner
• Oregon State University

Ethanol Workshop Series Oregon May 8, 2001
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Q. Is there enough cropland to produce both food
and fuel?
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Food Security is access by all people at all
times to enough food for an active, healthy life
(from a World Bank policy study, 1986)
There are approximately 200 definitions of the
term food security. The definition given above
is the one most-cited. (S. Maxwell, 1996)
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The simultaneous persistence of widespread
extreme food deprivation and plentiful food
supplies in a world with excellent means of
communications and transport, can only suggest
that there are fundamental flaws in the way in
which nations are functioning and the
relationships between them are governed and
managed. from FAO press release, January, 2001
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Do we have an obligation to feed the starving in
foreign countries?
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Is it morally defensible for affluent people to
spend money on luxuries for themselves while less
fortunate people are starving?
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Chemical Composition of Corn (percent of dry
matter)
Range Average
Starch 61.0 78.0 71.7
Protein 6.0 12.0 9.5
Fat 3.1 5.7 4.3
Ash 1.1 3.9 1.4
Cellulosea 3.3 4.3 3.3
Pentosansb 5.8 6.6 6.2
Sugarsc 1.0 3.0 2.
other 1.0
aplus lignin bas xylose cas glucose
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Corn Wet Milling
Adapter from C.R. Keim, 1999
Clean Corn
Steeps
Steep water (6.5)
Losses (1)
Germ System
Germ (8)
Mill and Screen System
Fiber (10.2)
Centrifugal Separator
Gluten (6.3)
Prime Starch (68)
Wash
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Enzymatic Starch Conversion
Adapter from H.S. Olsen, 1995
Starch Slurry
Liquefaction
Maltodextrin
?-amylase
Glucoamylase/ Pullulanase
Saccharification
To Fuel Ethanol
Maltose Syrups
Purification
Glucose Syrups
Mixed Syrups
Glucose Isomerase
Isomerization
Fructose Syrups
Refining
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Definitions
biomass A term commonly used when referring
to the relatively large amounts of heterogeneous
matter produced by living organisms. It includes
residues originating from plants, animals, and
microorganisms
lignocellulosic biomass Those biomaterials
whose composition is dominated by lignified cell
walls from vegetative plants.
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Polysaccharide and lignin content of
representative lignocellulosic feedstocks a,b
Component Lignocellulosic Material Lignocellulosic Material Lignocellulosic Material
Straw Cottonwood Pine
Glucan 31.9 42.4 42.4
Xylan 18.9 13.0 5.9
Arabinan 2.1 0.2 1.3
Mannan 0.2 2.0 11.0
Galactan 0.6 0.3 2.3
Lignin 22.8 22.7 27.1
sum of above 76.5 80.6 90.0
a values are percentages on a dry weight basis b
data taken from Puls and Schuseil (1992) c
measured as Klason lignin
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Biomass (cellulose, Hemicellulose, lignin)
Mechanical chipping/grinding
Milled Biomass
Pretreatment (Dilute acid, 180oC)
Prehydrolysate Liquid (xylose, 2-furaldehyde)
Pretreated solid (cellulose, lignin)
Enzymatic saccharification (fungal cellulases)
Fermentation
Ethanol
Hydrolysate Liquid (glucose)
Hydrolyzed Solid (lignin)
fermentation
Ethanol
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Q. Is there enough cropland to produce both food
and fuel?
A. It appears so, but does that mean we should
do it?