Microbial infections

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Chapter 29Microbial Biotechnology
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Traditional uses

• Lactic acid bacteria
• ferment sugars
• form lactic acid
• food preservation
• Examples
• sauerkraut (acid cabbage)
• silage
• cheese
• curdling--conversion of milk to solid mass
• ripening--flavor changes and protein hydrolysis

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Traditional uses

• Yeast
• ferment sugars
• produce CO2 and ethanol
• Saccharomyces cerevisiae
• wine
• fermentation of grapes
• crush grapes
• ferment in restricted air container
• variations
• red and white grapes
• other microorganisms for specific tastes

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Traditional uses

• Yeast
• beer
• amylase from malt
• breaks down starch
• yeast ferments sugar
• produces CO2 (foam) and ethanol

Figure 29.5
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Traditional uses

• Yeast
• Vinegar
• yeast ferments sugar
• juice
• Acetobacter spp.
• Oxidze ethanol to acetic acid and water

Figure 29.6
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Traditional uses

• Yeast
• bread
• raise bread
• bakers yeast (strain of S. cerevisiae)
• Mixed cultures
• kefir mildly alcoholic from bacteria and yeast
• soy sauce and miso mixed microorganisms

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Microbes as insecticides

• Certain Bacillus species
• mechanisms
• produce protein crystals
• parasporal bodies
• in insect gut ulcerates intestinal wall
• B. thuringiensis
• Bt control caterpillars and mosquito larvae
• B. popilliae
• Bp control Japanese beetles
• Nosema locustae (protozoan)
• grasshoppers, locusts and crickets

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Microbes as Chemical Factories

• Industrial fermentors
• Anaerobic fermentations
• end product
• commercial value
• Ethanol
• Acetone
• Butanol

Figure 29.8
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Microbes as Chemical Factories

• Aerobic processes
• Antibiotics
• penicillin
• Amino acids
• Enzymes

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Microbes as Chemical Factories

• Chemical Reactions
• microorganisms used in synthesis
• corticosteroids
• cortisone
• prednisone

Figure 29.9
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Genetically Engineered Microbes

• Medical uses
• recombinant DNA technology
• produce specific gene products on large scale
• hormones
• human growth hormone
• insulin
• other proteins
• tissue plasminogen activator
• streptokinase
• human DNase

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Genetically Engineered Microbes

• Agricultural uses
• Bt toxin
• Ice minus bacteria
• competes with bacteria which stimulate frost
  formation on plants
• Silage makers