Bioremediation and Biomass Utilization

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Dec 14, 2012 (4 years and 9 months ago)

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Chapter 14

Bioremediation and Biomass Utilization

Bioremediation


Xenobiotics


Chakrabarty

s

superbug



Cell surface
-
expressed enzymes


Radioactive environments

Utilization of starch & sugars (alcohol & fructose)

Utilization of cellulose (cellulosic biofuel)

Bioremediation and Xenobiotics


Bioremediation
-
The use of biological agents to
remove toxic wastes from the environment.


Xenobiotics
-
Unnatural chemicals such as
herbicides, pesticides, refrigerants, solvents, and
other organic compounds.

Copyright © 2010 ASM Press

American Society for Microbiology

1752 N St. NW, Washington, DC 20036
-
2904

Molecular Biotechnology: Principles and Applications of Recombinant

DNA,

Fourth Edition

Bernard R. Glick, Jack J. Pasternak, and Cheryl L. Patten

Chapter 14

Bioremediation and Biomass Utilization

Table 14.1

Pseudomonas

are soil
bacteria that degrade
xenobiotics to catechol or
protocatechuate thanks
to genes on their
plasmids.

Copyright © 2010 ASM Press

American Society for Microbiology

1752 N St. NW, Washington, DC 20036
-
2904

Molecular Biotechnology: Principles and Applications of Recombinant

DNA,

Fourth Edition

Bernard R. Glick, Jack J. Pasternak, and Cheryl L. Patten

Chapter 14

Bioremediation and Biomass Utilization

Figure 14.5

Chakrabarty et al. (1980) developed and patented a

superbug


that degraded petroleum
(camphor, octane, xylene, and naphthaline) by plasmid transfers.

Copyright © 2010 ASM Press

American Society for Microbiology

1752 N St. NW, Washington, DC 20036
-
2904

Molecular Biotechnology: Principles and Applications of Recombinant

DNA,

Fourth Edition

Bernard R. Glick, Jack J. Pasternak, and Cheryl L. Patten

Chapter 14

Bioremediation and Biomass Utilization

Figure 14.11

Figure 14.12

Expressing a
Pseudomonas

or
Flavobacterium

organophosphorus hydrolase (opd) gene fused
to a lipoprotein gene at the
E. coli
cell surface to degrade organophosphate pesticides.

Copyright © 2010 ASM Press

American Society for Microbiology

1752 N St. NW, Washington, DC 20036
-
2904

Molecular Biotechnology: Principles and Applications of Recombinant

DNA,

Fourth Edition

Bernard R. Glick, Jack J. Pasternak, and Cheryl L. Patten

Chapter 14

Bioremediation and Biomass Utilization

Figure 14.13

Deinococcus radiodurans
is naturally
resistant to high levels of radiation
(given its enhanced DNA repair
system) and hence an ideal bacteria
to express bioremediating proteins in
toxic, radioactive environments.

Copyright © 2010 ASM Press

American Society for Microbiology

1752 N St. NW, Washington, DC 20036
-
2904

Molecular Biotechnology: Principles and Applications of Recombinant

DNA,

Fourth Edition

Bernard R. Glick, Jack J. Pasternak, and Cheryl L. Patten

Chapter 14

Bioremediation and Biomass Utilization

Figure 14.16

Biomass (e.g., starch) is used to generate
alcohol and fructose thanks largely to the
action of 3 key enzymes.

Copyright © 2010 ASM Press

American Society for Microbiology

1752 N St. NW, Washington, DC 20036
-
2904

Molecular Biotechnology: Principles and Applications of Recombinant

DNA,

Fourth Edition

Bernard R. Glick, Jack J. Pasternak, and Cheryl L. Patten

Chapter 14

Bioremediation and Biomass Utilization

Figure 14.25

Cellulose is composed of
b
-
1,4 linked glucose and can be used for biofuel (ethanol) if it can
be extracted from the plant cell wall and broken down into glucose residues.

The Plant Cell Wall

a | Cell wall containing cellulose microfibrils, hemicellulose, pectin, lignin and soluble proteins.

b | Cellulose synthase enzymes are in rosette complexes, which float in the plasma membrane.

c | Lignification occurs in the S1, S2 and S3 layers of the cell wall.

Cellulosic Ethanol Production
and Research Challenges

This figure depicts some key processing
steps in a future large
-
scale facility for
transforming cellulosic biomass (plant
fibers) into biofuels. Three areas where
focused biological research can lead to
much lower costs and increased
productivity include developing crops
dedicated to biofuel production (see step
1), engineering enzymes that deconstruct
cellulosic biomass (see steps 2 and 3), and
engineering microbes and developing new
microbial enzyme systems for industrial
-
scale conversion of biomass sugars into
ethanol and other biofuels or bioproducts
(see step 4). Biological research challenges
associated with each production step are
summarized in the right portion of the
figure.

Potential Bioenergy Crops