Chapter 13-Synthesis of commercial
products by recombinant microbes
Restriction enzymes
Small molecules
Antibiotic genes
Biopolymers
Restriction enzymes are great products for
recombinant microbes (E. coli)
• $350 million in annual RE sales in 2007
• Some microbes are difficult or expensive to grow in
culture
• Strategy: clone the gene for the RE from a given
microbe and express it in E. coli (along with the
corresponding modification [methylase] gene for
protection of the E. coli DNA)
• E. coli is simple to grow
Chapter 13
Synthesis of Commercial Products by Recombinant Microorganisms
Figure 13.1
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 13
Synthesis of Commercial Products by Recombinant Microorganisms
Figure 13.2
Method for cloning and
selecting the gene for the
restriction enzyme PstI
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 13
Synthesis of Commercial Products by Recombinant Microorganisms
Figure 13.3
Method for cloning and
selecting the gene for the
Dde I restriction enzyme and
the Dde I methylase
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
Small molecules are also great products for
recombinant microbes (often E. coli)
• Indigo (Fig. 13.10)
• Ascorbic acid (Vitamin C)
• Amino acids (e.g., Glutamic acid or Glu for production of the flavor
enhancer MSG)
• Antibiotics, novel antibiotics and polyketide antibiotics
• Note that in all of these cases, one needs to clone the genes encoding the
enzymes making these metabolites in order to create or alter a biochemical
pathway
Chapter 13
Synthesis of Commercial Products by Recombinant Microorganisms
Table 13.1
Cloning amino acid
biosynthetic genes
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 13
Synthesis of Commercial Products by Recombinant Microorganisms
Table 13.3
Cloning antibiotic biosynthetic genes
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
Biopolymers are also great products for
recombinant microbes
• Xanthan gum production in Xanthomonas compestris
(genetically engineered to grow on whey, a lactose-rich
byproduct of cheese production)
• Melanins
• Animal adhesive proteins (from the blue mussel)
• Rubber (from the rubber plant Hevea brasiliensis)
• Biodegradable plastics (polyhydroxyalkanoates)
• Note that in all of these cases, one needs to clone the genes
encoding enzymes in order to create or alter a biochemical
pathway
Chapter 13
Synthesis of Commercial Products by Recombinant Microorganisms
Figure 13.31
Structure of xanthan gum (glucose backbone with Man-GluA-Man trisaccharide sidechains)
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 13
Synthesis of Commercial Products by Recombinant Microorganisms
Engineering of the E. col lacZ (encoding b-galactosidase) and lacY (encoding
Figure 13.32 lactose permease) genes for constitutive expression in Xanthomonas campestris.
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 13
Synthesis of Commercial Products by Recombinant Microorganisms
Figure 13.36
The enzymes responsible for the
production of this biodegradable
plastic were cloned from Alcaligenes
eutrophus and transferred to E. coli to
make even more of this biodegradable
plastic.
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
Summary
• I do not expect you to memorize all of the genetic
engineering details provided in the numerous
examples presented in this chapter; however, I do
want you to be familiar with the various strategies
that are employed in these examples.
• Specifically, note the common strategy that a gene
for an enzyme is transferred into a microbe which
alters the metabolic products of that microbe (i.e.,
metabolic engineering).