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

HO2CCO2H

HO2CCO2H

HO2CCO2H

OH

Succinic acid Fumaric acid (S)-Malic acid

OHO2C CO2HHO2C

CO2H

OH

OH

OH

OH

HO2C CO2H

NH2

Furan dicarboxylicacid

Glucaric acid Glutamic acid

The Winners

HO2CCO2H

HO2C

O OO

HO

Itaconic acid Levulinic acid Hydroxybutyrolactone

HO OH

OHHO

OH

OH

OH

OH

OH

HO OH

OH OH

OH

Glycerol Sorbitol Xylitol

HO OH

OH OH

OH

pseudo-chiralcenter

HO2COH

Arabinitol 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

HO2CCO2H

HO2CCO2H

HO2CCO2H

OH

Succinic acid Fumaric acid (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

HO2CCO2H

RNH2

NO

R

H

HOOH

H

H2OO

H2O

OO

Biochemical Pathway to Itaconic Acid

GlucoseO2C

CH3

O

Pyruvate

CO2

CoAS

CH3

Acetyl CoA

CO2

O2CCO2

O

OxaloacetateO2C CO2

HO CO2

Citrate

H2O

O2C CO2

CO2

Aconitate

CO2

O2CCO2

Itaconate

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

CO2HHO2C

Primary Transformations of Itaconic Acid

HO2CCO2H

Direct polymerization ?

RNH2

NO

R

OO

H2O

H

HOOH

O

H

H2O

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.