Transcript Fort - Department of Chemistry

Value Added Chemicals from Sugar
Feedstocks
Professor Ray Fort
Department of Chemistry
Based on
“Top Value Added Chemical from Biomass
Vol. 1: Results of Screening for Potential
Candidates from Sugars and Synthesis Gas”
Eds. T. Werpy and G. Petersen
Pacific Northwest Laboratory
And
National Renewable Energy Laboratory
Criteria for Selecting Chemicals
 Obtainable from sugars derived from cellulose,
hemicellulose, or starch
 At least two functional groups
 [Potentially] convertible to high value chemicals
 Data on [potential] market value
 Potential to become super-commodity chemicals
The Winners
OH
HO2C
CO2H
HO2C
CO2H
OH
OH
HO2C
HO2C
O
CO2H
CO2H
Furan dicarboxylic
acid
OH
OH
Glucaric acid
CO2H
(S)-Malic acid
Fumaric acid
Succinic acid
HO2C
HO2C
CO2H
NH2
Glutamic acid
The Winners
HO
HO2C
HO2C
CO2H
O
OH
OH
HO
Hydroxybutyrolactone
Levulinic acid
Itaconic acid
OH
OH
HO
OH
OH
OH
Glycerol
OH
Xylitol
pseudochiral
center
OH
HO2C
OH
OH
Arabinitol
OH
OH
OH
HO
OH
HO
Sorbitol
OH
O
O
Hydroxypropionic
acid
These compounds divide fairly well into two groups:
 Those with the same carbon number and carbon
skeleton as the sugars
 Those with fewer carbons or altered carbon
skeletons
All of the first group are typically produced by
simple chemical methodology. For example:
 Sorbitol by catalytic hydrogenation of glucose
 Levulinic acid by acid catalyzed dehydration
of sugars
 Glucaric acid by oxidation of starch with nitric
acid or hypochlorite
 Xylitol by catalytic hydrogenation of xylose
With one exception, all of the second group
are produced biologically. For example:
 Glycerol by yeast fermentation of sugars,
(and by hydrolysis of fats and oils)
 Glutamic acid by fermentation of glucose
or xylose with B. subtilis or genetically
modified E. coli
 Hydroxypropionic acid by anaerobic
fermentation of glucose
OH
HO2C
CO2H
Succinic acid
HO2C
Fumaric acid
CO2H
HO2C
CO2H
(S)-Malic acid
 Overexpression of succinate has been
engineered in numerous strains of E. coli
 Knocking out other NADH consuming
pathways increases yield, up to 130%
 Some strains will utilize xylose as well as
glucose
 Purity of feedstock an issue when using
biomass: phenolics from lignin inactivate bugs
 Flow systems with immobilized bacteria have
been tested
Primary Transformations of Succinic Acid
H
OH
HO
HO2C
RNH2
CO2H
N
H2O
R
H
H2 O
O
O
O
O
Biochemical Pathway to Itaconic Acid
CO2
O2C
Glucose
Itaconate
O2C
CoAS
CO2
O
CH3
CH3
Pyruvate
Acetyl CoA
CO2
CO2
CO2
O2C
CO2
O
O2C
Aconitate
CO2
HO
O2C
Oxaloacetate
Citrate
CO2
CO2
H 2O
 Itaconic acid secreted by fungi to acidify their
environment
 Chief fungus employed is Aspergillus terreus
 With glucose substrate, yields are 40-60%
 Five-carbon sugars give only 15-30%
 Isomerization to the more stable citraconic acid
is a problem
HO2C
CO2H
Primary Transformations of Itaconic Acid
Direct polymerization ?
HO2C
CO2H
H
RNH2
H2 O
HO
OH
R
H
H2O
O
O
N
O
O
Major Issues
 Startup requires large capital investment
 Petroleum-based competitors still
relatively cheap
 Competition from biomass-to-fuel
 Heterogeneity, purity of feedstocks
 Relative fragility of bacteria, fungi
Thanks to my colleagues Joe Genco and
Barbara Cole for helpful discussions.