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.
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.
Molecular Biotechnology: Principles and Applications of Recombinant DNA, Fourth Edition
Bernard R. Glick, Jack J. Pasternak, and Cheryl L. Patten
Copyright © 2010 ASM Press
American Society for Microbiology
1752 N St. NW, Washington, DC 20036-2904
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.
Molecular Biotechnology: Principles and Applications of Recombinant DNA, Fourth Edition
Bernard R. Glick, Jack J. Pasternak, and Cheryl L. Patten
Copyright © 2010 ASM Press
American Society for Microbiology
1752 N St. NW, Washington, DC 20036-2904
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.
Molecular Biotechnology: Principles and Applications of Recombinant DNA, Fourth Edition
Bernard R. Glick, Jack J. Pasternak, and Cheryl L. Patten
Copyright © 2010 ASM Press
American Society for Microbiology
1752 N St. NW, Washington, DC 20036-2904
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.
Molecular Biotechnology: Principles and Applications of Recombinant DNA, Fourth Edition
Bernard R. Glick, Jack J. Pasternak, and Cheryl L. Patten
Copyright © 2010 ASM Press
American Society for Microbiology
1752 N St. NW, Washington, DC 20036-2904
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.
Molecular Biotechnology: Principles and Applications of Recombinant DNA, Fourth Edition
Bernard R. Glick, Jack J. Pasternak, and Cheryl L. Patten
Copyright © 2010 ASM Press
American Society for Microbiology
1752 N St. NW, Washington, DC 20036-2904
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.
Molecular Biotechnology: Principles and Applications of Recombinant DNA, Fourth Edition
Bernard R. Glick, Jack J. Pasternak, and Cheryl L. Patten
Copyright © 2010 ASM Press
American Society for Microbiology
1752 N St. NW, Washington, DC 20036-2904
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 industrialscale 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