ABBOTTS
BIOTECHNOLOGY
BIOTECHNOLOGY
• the use of micro-organisms by humans to make
substances, humans want
• E.g. In the manufacture of food, antibiotics,
biogas
These substances include:
Medicines
antibiotics and insulin
Food
Maas, bread, wine and cheese
Antibiotics
• Antibiotics can be made naturally by a process
called biosynthesis
• It involves the formation of a chemical
compound by a living organism
• Natural antibiotics are made by fungi
▫ E.g. Penicillium which grows on fruit
▫ Streptomyces which grows in soil
INSULIN PRODUCTION
• Insulin is a hormone which regulates the
concentration of blood sugar
• People suffering from diabetes mellitus cannot
make insulin
• Have to have daily injections of insulin
• Used to get insulin from pigs
• Today genetic engineering has produced
bacteria which can make human insulin
• Bacteria are grown in large vats
• Insulin is extracted and purified
TRADITIONAL TECHNOLOGY
ANAEROBIC RESPIRATION
• Many of these processes involve
anaerobic respiration – respiration
without oxygen
• Sugars are changed into alcohol and
carbon dioxide – alcoholic fermentation
• During this process, in the presence of
sugar, some bacteria and fungi
produce:
▫ fermented foods
▫ alcoholic drinks
▫ breads
Sugars are changed into alcohol
And large quantities of carbon dioxide
TRADITIONAL TECHNOLOGY IN
FOOD PRODUCTION
▫ SORGHUM BEER
▫ MAAS
▫ MAHEWU
8
ALCOHOLIC DRINKS BEER
• Beer is made by a process known
as brewing
• Dried, crushed germinating barley
seeds (contain the sugar maltose),
water, hops (for flavour) and yeast
are mixed
• Yeast respires anaerobically
producing alcohol and carbon
dioxide (gives beer the bubbles)
• When fermentation is complete the
excess yeast is skimmed off and is
used to produce yeast extracts such
as Marmite
MAHEWU
TRADITIONAL SOUTH AFRICAN BEER
• Traditional South African nonalcoholic energy providing drink
• Made from fermented maize meal or
sorghum, malt, yeast and water
• Commercially available at
supermarkets
• Similar to mealie meal but with sugar
changed to lactic acid during
fermentation
• Commercial preparations are often
enriched with vitamins and minerals
ALCOHOLIC DRINKS - WINE
• Wine is produced from
grapes
• Can be made from many
other types of fruit
• Yeast cells found on the
grape skins ferment grape
sugar turning it into alcohol
and carbon dioxide
• Grape juice is allowed to
ferment
• and bottled
BACTERIA IN THE FOOD INDUSTRY
• Fermented dairy products
• The bacterium Lactobacillus acidophilus
causes pasteurised milk to ferment
• Lactose is converted into lactic acid
• Lowers the pH of the milk
• Causes the protein caseinogen to
coagulate starting process for making
yoghurt and some cheeses
• The increased acidity prevents the
proliferation of pathogenic bacteria
BACTERIA IN THE FOOD INDUSTRY
• Cheese making
• An enzyme rennin is added to curdled
(acidified) milk
• Causes further coagulation forming curds
and whey
• Curds and whey are separated
• Curds are drained and pressed into cheese
• To produce a variety of cheeses, different
incubation periods, milks and bacteria are
used
• Process is complicated
• Can take from months to a year to complete
EXTRA
NON-DAIRY FERMENTED FOOD
PRODUCTS
• Acetic and lactic acid are
produced by fermentation
bacteria
• The acids protect the food
against decay
• Fermented foods – pickles,
olives, sauerkraut, cured
meats and fish – are
usually produced by lactic
acid bacteria
• Vinegar is produced by
acetic acid bacteria acting
on wine, cider or other
alcoholic beverages to
produce acetic acid
FUNGI IN THE FOOD INDUSTRY
• Yeast and certain moulds are used in
biotechnology
• Yeast is a unicellular fungus
• It is the smallest fungus but it is economically
extremely important in the production of bread
and alcoholic drinks
EXTRA
BREAD MAKING
• Bread is made from a
mixture of flour, a little
sugar and yeast
• During the process
yeast ferments sugar
and gives off carbon
dioxide and alcohol
• Carbon dioxide makes
the dough rise while
alcohol evaporates
• THE END