FOOD FROM MICROORGANISMS:

FUNGI, BACTERIA AND FERMANTATION

OBJECTIVESTo recall the method of nutrition used by

microorganisms

To know some examples of commercial exploitation of microbial metabolism

What is heterotroph?

herbivores

carnivores

omnivoresAll

animals

Most bacteri

a

Some fungi

MICROBES CARRY OUT USEFUL METABOLIC PROCESSES

Heterotrophic

Fungi -such as yeast and Fusarium- and many bacteria saprotrophic

The enzymes, toxic or excess products which they excrete of use to humans

Some microbes useful in food production

Acetobacter vinegar manufacture

Lactobacillus yoghurt and cheese production

‘Ripening’ bacteria cheese production

Fusarium and mycoprotein

On an enormous scale in special factories

The microbes

cultured separately added sterilised container

These containers

fermenters or bioreactors

ÖZNUR WILL <3

Commercial Food ProductionThe fermentation processes used to grow the

microbes must be economical and efficient, and methods are always being improved.

Cheese production is a traditional process that has been updated by the use of modern scientific techniques.

The curds are formed more quickly if the coagulation of the milk protein casein is catalysed by an enzyme.

Traditionally rennin was used, extracted from the stomach contents of calves slaughtered for meat.

Genetic engineers have now produced a strain of the bacterium E.

Coli which contains the gene for the enzyme chymosin.

This enzyme can be used instead of rennin to produce a cheese that is acceptable to vegetarians.

The second phase of cheese production also involves the action of bacteria or fungi – hard cheeses such as Stilton are formed by bacterial action from the inside, whereas soft cheeses are usually the result of fungal action from the outside.

The characteristic smells of strong cheeses are usually due to metabolism of fatty acids, sometimes the same as those found on human skin.

The warm, moist conditions on the feet produce and odour which the producers of Camembert cheese call ‘les pieds de dieu’ (God’s feet).

Bread and beer are produced using yeast to ferment a sugar source.

NİSA WILL

<3

Yeast from alcoholic fermentation= cattle food

Fungi form bioreactor-to produce food for humans.

Mycoprotein

AdvantagesProduced quicklyProduced cheaplyTaking up a little areaControlled environmentSame qualityHigh protein contentLower fat contentEasily shaped and flavoured

Cheese ProductionPasteurised milkStarter culture “ Lactobacillus”Milk solids-pressed to remove water.Other bacteria and fungi- give flavour.

Bacteria the production of foodVinegar aerobic fermantation of alcohol

referenceshttp://www.biology-online.org/dictionary/Heterotroph

COMPLETE BIOLOGY FOR IGCSE