Introduction to Industrial Microbiology
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Questions and Answers

What are primary metabolites primarily associated with?

  • Growth phase of cells (correct)
  • Accumulation during the stationary phase
  • Production of antibiotics
  • Synthesis of microbial cells (correct)

    • Which of the following is NOT classified as a secondary metabolite?

  • Mycotoxins
  • Organic acids (correct)
  • Amino acids (correct)
  • Penicillin

    • During which phase are secondary metabolites primarily produced?

  • Idiophase (correct)
  • Log phase
  • Lag phase
  • Trophophase

    • Which of the following products is considered a primary metabolite?

    <p>Ethanol</p> Signup and view all the answers

    What is the term for the phase where microorganisms produce primary metabolites?

    <p>Trophophase</p> Signup and view all the answers

    Which type of product includes enzymes associated with microbial cells?

    <p>Primary metabolites</p> Signup and view all the answers

    Which statement about secondary metabolites is true?

    <p>They accumulate during the idiophase.</p> Signup and view all the answers

    What types of products can microorganisms produce in industrial microbiology?

    <p>Fuels, solvents, and organic acids</p> Signup and view all the answers

    What are primary metabolites primarily synthesized during?

    <p>Exponential phase of growth</p> Signup and view all the answers

    Which of the following is NOT considered a primary metabolite?

    <p>Penicillin</p> Signup and view all the answers

    Why are microbial fermentations economically competitive for producing primary metabolites?

    <p>They produce biologically active isomers</p> Signup and view all the answers

    What aspect of microbial metabolism ensures it does not overproduce compounds?

    <p>It conserves energy and nutrients</p> Signup and view all the answers

    During which phase of cell growth does the accumulation of secondary metabolites typically lag?

    <p>During the exponential phase</p> Signup and view all the answers

    What is a common limitation related to the optimal growth conditions for microbial synthesis of secondary metabolites?

    <p>Optimal conditions for growth often differ from those needed for metabolite synthesis</p> Signup and view all the answers

    Which compound is categorized as a primary metabolite of catabolic metabolism?

    <p>Citric acid</p> Signup and view all the answers

    What factor has increased interest in microbial production of certain compounds recently?

    <p>Increased cost of petroleum</p> Signup and view all the answers

    What is the primary mechanism responsible for the regulation of anabolic enzymes in biosynthesis?

    <p>Feedback regulation</p> Signup and view all the answers

    How does feedback inhibition primarily work in metabolic pathways?

    <p>By binding to an allosteric site on the first enzyme</p> Signup and view all the answers

    What is the role of the end product in feedback repression?

    <p>It serves as a co-repressor.</p> Signup and view all the answers

    Which form of regulation acts rapidly to switch off the biosynthesis of an end product?

    <p>Feedback inhibition</p> Signup and view all the answers

    In linear pathways producing a single end product, which action is typically observed?

    <p>Inhibition of the first enzyme by the end product</p> Signup and view all the answers

    What happens to the apo-repressor in the presence of its co-repressor?

    <p>It transforms into an active repressor.</p> Signup and view all the answers

    Which type of metabolic pathways involves more complex control mechanisms?

    <p>Branched pathways</p> Signup and view all the answers

    What is one of the outcomes of feedback regulation in metabolic processes?

    <p>Preventing unnecessary synthesis of intermediates.</p> Signup and view all the answers

    What type of feedback control involves more than one end product exerting control over the first enzyme?

    <p>Concerted/multivalent feedback control</p> Signup and view all the answers

    In which feedback control mechanism do end products inhibit the first enzyme to a certain percentage independently?

    <p>Cumulative feedback control</p> Signup and view all the answers

    Which feedback control mechanism ensures that control occurs immediately after the branch point to an end product when that product is in excess?

    <p>Sequential feedback control</p> Signup and view all the answers

    What is the role of isoenzymes in metabolic control?

    <p>They catalyze reactions differently based on end product concentrations.</p> Signup and view all the answers

    What is the ideal characteristic of an industrial microorganism's metabolism in relation to the product of interest?

    <p>It should produce more product than required for growth.</p> Signup and view all the answers

    Which of the following statements is true regarding cooperative feedback control?

    <p>Weak control is replaced by strong control in the presence of all end products.</p> Signup and view all the answers

    How are modifications in industrial microorganisms typically achieved for strain improvements?

    <p>By losing the end products that control key enzymes.</p> Signup and view all the answers

    Which of the following describes the consequence of an organism not recognizing inhibiting levels of normal control metabolites?

    <p>Overproduction of desired products.</p> Signup and view all the answers

    What is the primary goal of intensive mutagenesis followed by screening and selection in industrial production?

    <p>To increase the efficiency of primary metabolite production.</p> Signup and view all the answers

    How can gene overexpression enhance a metabolic pathway?

    <p>By mutations in promoter regions or increasing gene copy numbers.</p> Signup and view all the answers

    What role do auxotrophic mutants play in the production of primary metabolites?

    <p>They require external nutrients to promote overproduction of other metabolites.</p> Signup and view all the answers

    What happens to the metabolic pathway control when biotin levels are insufficient in Corynebacterium glutamicum?

    <p>Glutamate is produced instead of lactate.</p> Signup and view all the answers

    Which of the following contributes to increased permeability in biotin-limited cells?

    <p>A change in the fatty acid and phospholipid content.</p> Signup and view all the answers

    What is a likely consequence of adding penicillin during biotin limitation?

    <p>Excretion of glutamate from the cells.</p> Signup and view all the answers

    What effect does feedback inhibition have in metabolic pathways?

    <p>It prevents the activity of enzymes involved in the pathway.</p> Signup and view all the answers

    Why would a glycerol requiring auxotrophic mutant excrete glutamate?

    <p>When phospholipid synthesis is regulated by glycerol supply.</p> Signup and view all the answers

    Study Notes

    Introduction to Industrial Microbiology

    • Industrial microbiology is the study of microorganisms used to produce various compounds and transform substrates.
    • Microbial products are classified as primary and secondary metabolites.
    • Primary metabolites are compounds related to the synthesis of microbial cells and are formed during the growth phase (trophophase).
    • Examples of primary metabolites include amino acids, nucleotides, ethanol, and organic acids.
    • Secondary metabolites accumulate after the active growth phase (idiophase) and are not directly related to cell synthesis.
    • Examples of secondary metabolites include antibiotics and mycotoxins.

    Microbial Synthesis of Primary Metabolites

    • Primary metabolites are produced during the exponential growth phase of microorganisms.
    • These metabolites include intermediates and end products of anabolic and catabolic metabolism.
    • Key primary metabolites for industrial use include amino acids, nucleotides, vitamins, solvents, and organic acids.
    • Microbial fermentations are often economically competitive for producing primary metabolites compared to chemical synthesis.

    Control of Primary Metabolism

    • Microbial metabolism is a conservative process that avoids wasteful production of compounds.
    • Regulatory control mechanisms ensure efficient production of enzymes and metabolites, such as feedback inhibition and covalent modifications.
    • Feedback regulation involves the end product of a pathway inhibiting the first enzyme of the pathway, either at the enzyme level (feedback inhibition) or the synthesis level (feedback repression).
    • Feedback inhibition is a rapid control mechanism that switches off the biosynthesis of an end product.
    • Feedback repression switches off the synthesis of redundant enzymes.
    • Branched pathways are controlled by various mechanisms, including concerted/multivalent feedback control, cooperative feedback control, cumulative feedback control, sequential feedback control, and isoenzyme control.

    Approaches to Strain Improvements

    • Ideal industrial microorganisms require deregulation of their metabolism to produce high yields of desired products.
    • The enhancement of a metabolic path can be achieved by gene overexpression through point mutations in promoter regions or increased copy number of genes.
    • Prevention of byproducts can be achieved by searching for auxotrophic mutants.

    Modification of Permeability

    • An example of permeability modification is seen in the glutamic acid fermentation by Corynebacterium glutamicum.
    • Biotin levels influence glutamate excretion, with low levels leading to glutamate excretion and high levels leading to lactate production.
    • This permeability change is linked to alterations in the fatty acid and phospholipid content of the cell envelope.
    • The inclusion of penicillin or fatty acid derivatives during exponential growth under biotin limitation also causes glutamate excretion.
    • Auxotrophic mutants requiring glycerol for phospholipid synthesis can also lead to glutamate excretion.

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    Major Products Of Industrial Microbiology PDF

    Description

    This quiz explores the fundamentals of industrial microbiology, focusing on the production of primary and secondary metabolites by microorganisms. Key concepts include the growth phases of microorganisms and their contributions to industrial processes through various microbial products. Test your knowledge on essential metabolites and their applications.

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