13
Chapter 13-Synthesis of commercial products by recombinant microbes Restriction enzymes Small molecules Antibiotic genes Biopolymers
Chapter 13-Synthesis of commercial products by recombinant microbes
Restriction enzymesSmall moleculesAntibiotic 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
Copyright © 2010 ASM PressAmerican Society for Microbiology
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Molecular Biotechnology: Principles and Applications of Recombinant DNA, Fourth EditionBernard R. Glick, Jack J. Pasternak, and Cheryl L. Patten
Chapter 13Synthesis of Commercial Products by Recombinant Microorganisms
Figure 13.1
Copyright © 2010 ASM PressAmerican Society for Microbiology
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Molecular Biotechnology: Principles and Applications of Recombinant DNA, Fourth EditionBernard R. Glick, Jack J. Pasternak, and Cheryl L. Patten
Chapter 13Synthesis of Commercial Products by Recombinant Microorganisms
Figure 13.2
Method for cloning and selecting the gene for the restriction enzyme PstI
Copyright © 2010 ASM PressAmerican Society for Microbiology
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Molecular Biotechnology: Principles and Applications of Recombinant DNA, Fourth EditionBernard R. Glick, Jack J. Pasternak, and Cheryl L. Patten
Chapter 13Synthesis 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
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
Copyright © 2010 ASM PressAmerican Society for Microbiology
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Molecular Biotechnology: Principles and Applications of Recombinant DNA, Fourth EditionBernard R. Glick, Jack J. Pasternak, and Cheryl L. Patten
Chapter 13Synthesis of Commercial Products by Recombinant Microorganisms
Table 13.1
Cloning amino acid biosynthetic genes
Copyright © 2010 ASM PressAmerican Society for Microbiology
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Molecular Biotechnology: Principles and Applications of Recombinant DNA, Fourth EditionBernard R. Glick, Jack J. Pasternak, and Cheryl L. Patten
Chapter 13Synthesis of Commercial Products by Recombinant Microorganisms
Table 13.3 Cloning antibiotic biosynthetic genes
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
Copyright © 2010 ASM PressAmerican Society for Microbiology
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Molecular Biotechnology: Principles and Applications of Recombinant DNA, Fourth EditionBernard R. Glick, Jack J. Pasternak, and Cheryl L. Patten
Chapter 13Synthesis of Commercial Products by Recombinant Microorganisms
Figure 13.31
Structure of xanthan gum (glucose backbone with Man-GluA-Man trisaccharide sidechains)
Copyright © 2010 ASM PressAmerican Society for Microbiology
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Molecular Biotechnology: Principles and Applications of Recombinant DNA, Fourth EditionBernard R. Glick, Jack J. Pasternak, and Cheryl L. Patten
Chapter 13Synthesis of Commercial Products by Recombinant Microorganisms
Figure 13.32Engineering of the E. col lacZ (encoding -galactosidase) and lacY (encoding lactose permease) genes for constitutive expression in Xanthomonas campestris.
Copyright © 2010 ASM PressAmerican Society for Microbiology
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Molecular Biotechnology: Principles and Applications of Recombinant DNA, Fourth EditionBernard R. Glick, Jack J. Pasternak, and Cheryl L. Patten
Chapter 13Synthesis 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.
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).
