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BIO 205

Chapter 27
Useful Microbes
Microorganisms in Industry

Produce Many Useful
Organic Compounds

•Primary metabolites
are directly involved in
normal growth,
development, and
Many secondary metabolites have value as food additives,
pharmaceuticals, vitamins, etc.
•Secondary metabolites have important ecological functions,
and are often species specific.
Microorganisms Also Produce Important Enzymes and
Other Products
Some enzymes are important commercially, such as:

1. amylase
2. pectinase
3. several proteases

Streptokinase breaks down blood clots formed during a

heart attack

Hyaluronidase facilitates absorption of fluids injected under

the skin

Lactones produced by species of fungi are used for flavor

and aroma enhancement
Beer Is Produced by
the Fermentation of
Malted Barley
Wine Is Produced by the Fermentation of Fruit or Plant Extracts

Fruit or plant materials are crushed to produce juice (must)

Yeasts are added to begin fermentation in anaerobic conditions

The wine is aged in wooden casks, where unique flavor and aromas
develop based on:

•cask wood
•organic compounds in the fruit/plant
•Distilled Spirits Contain More Alcohol than Beer or Wine

•Ethyl alcohol results from distillation of fermented fruits or

Other Microbial Products
Many Antibiotics Are the Result of Industrial Production

Penicillin was the first antibiotic to be produced on an

industrial scale

Antibiotic production can involve fermentation, producing

natural antibiotics or semisynthetic drugs

S. griseus
Some Microbial Products Can Be Used to Control Insects

•A microbial toxin insecticide should be quick and specific to an insect


•Bacillus thuringiensis produce a toxin (Bt-toxin) during sporulation that

is deposited on leaves

•If ingested by caterpillars, the toxin lyses the gut wall causing
paralysis and bacterial invasion

•It seems to be harmless to plants and humans

B. thuringiensis

Dead Cabbage Butterfly Larva

•Fungal Organisms Also Are Being Commercially Developed

•Yeast cells are grown in fermentors

•They are sold as dry yeast or compressed yeast cakes

•Many species of mushrooms are grown on farms

•High humidity and cool temperatures are required for

mushroom growth
Agaricus bisporis
Bioremediation Helps Clean
Up Pollution Naturally

Naturally occurring
Pseudomonas species
can be stimulated to
degrade oil in spills

Species of Arthrobacter
degrade oil and allow plant
growth in spill regions

Exxon Valdvez
Anaerobic and aerobic bacteria can reduce polychlorinated
biphenyls (PCBs) to:

•carbon dioxide
•hydrogen chloride

Bacteria can degrade trichloroethylene (TCE) in contaminated

ground water

Deinococcus radiodurans may be used to clean up:

•radioactive waste
•ionic mercury compounds

Bacteria can reduce levels of TNT in soil surrounding weapons

•Industrial Genetic Engineering Continues to Make Advances

•Bacterial plasmids can be used to transfer a foreign gene

into a targeted bacterial cell

•Traits like antibiotic resistance and antibiotic production

can be transferred

Scientists hope to insert genes from Rhizobium into grain
plants, removing the need for fertilizer

Biotechnology may also be used to disrupt pathogen life cycles

to prevent disease
End of Chapter 27