Biosynthesis of Bio-friendly Polymers U.S. Wood, Paper and - - PDF document

Biosynthesis of Bio-friendly Polymers

U.S. Wood, Paper and Hydrocarbons

• U.S. forest product industry

– 1.3 million employees – Estimated payroll of 50 billion dollars

• U.S. imports of paper and wood products have

increased

– Closure of 350 paper and wood mills (1995-2005) – Loss of more than 150,000 jobs

• 2005 oil consumption 20.8 million barrels/day
• Imported hydrocarbons make of 59% total

consumption – 20% result in plastics and chemical building blocks

Biocatalysts in Organic Chemistry

• Advantages of Biocatalysts

– Mild reaction conditions – High stereoselectivity – Do not require co-factors – Catalysts recyclability – Avoid organic solvents and toxic catalysts

• Common Biocatalysts

– Lipases (i.e. Candida antartica, Psuedomonas cepacia, etc.)

Candida antarctica lipase B

• Isolated in 1990
• 33 kDa
• 2 binding sites

– Acyl-binding site – Alcohol binding site

• Member of Serine

Hydrolase class

• Catalytic ability up to

130°C

Taken from Raza et al. Protein Science (2001), 10:329-338.

CALB catalyzed Polymerization Reactions

HO OH O O

x

+

HO OH

y

Lipase

O O O O

y x n

Esterification and Transesterifications Ring-opening polymerization of lactones, carbonates, depsipeptides, etc.

O O

Lipase

O O

n

CALB catalyzed Bond Formation

Amide Bonds: Aminolysis and Ammonolysis of esters

R OEt O

Lipase, NH3

R NH2 O Lipase, R3NH2,

R O R2 O R NHR3 O

Carbamate Bonds: Alkoxycarbonylation of vinyl carbonates

R1O O H2N R2 R1O N H R2 O O

+ Lipase

Carbon-Carbon bonds: Michael additions and Aldol reactions

R1 R1 R2 O O O

+

Lipase

R1 R1 R2 O O O

+ O O

+ Lipase

OH O

More Possibilities

O O O +

CALB, 70 °C Solvent

+

O O H OH O

N H2 NH2

2

O O NH NH O O O O O O

n

CALB, 95 °C

O O NH H O NH O O O H

Michael Donors

N H NH2

n-phenylethylenediamine

HS SH

1,3-propanedithiol

HS SH

1,2-ethyldithiol

HS SH

1,5-pentanedithiol

HS

1-pentanethiol

HS

1-butanethiol

O

2-cyclohexen-1-one

O

3-methylcyclohex-2-enone

O O

Methyl methacrylate

N H

diethylamine

Michael Acceptors

Current Investigations

N

acrylonitrile

HS SH

1,3-propanedithiol +

N S SH

Michael Adduct Molecular Weight 161 CALB HS SH

1,2-ethyldithiol

HS SH

1,5-pentanedithiol

HS

1-pentanethiol

HS

1-butanethiol

Molecular Operating Environment

S R

(S)- α− hydroxy valeric acid preferred by CALB

Adam et al. European Journal of Organic Chemistry 1998, 2013-2018.

Renewable Feedstocks

O HO O OH O

β- ketoadipic acid

O OH O HO O

β-ketoglutaric acid

NH2 O HO O OH

Glutamate

O OH O HO OH

2-hydroxyglutaric acid

Acknowledgments

• NSF
• Georgia Institute of Technology
• Dr. Sheldon May and Group
• Dr. Charlie Oldham