Page 117 - Biology_F5

Biology for Advanced Level Secondary Schools

3.3.4 Economic importance of monerans such as leaf litter, dead logs and animals
Bacteria have a wide range of economic into simple substances like nutrients, which
importance to humans and other can be easily absorbed by other plants.
organisms. Furthermore, many bacteria This process is called decomposition and
serve important roles in both industries it ensures nutrients recycling. It is vital to
and agriculture. nature because it unlocks nutrients locked
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in dead bodies of other organisms and
Advantages of monerans makes them available to others.

(a) Production of vinegar
Some bacteria, such as those of genera (e) Treatment and purification of
Acetomonas and Acetobacter are used in waste water or sewage
making vinegar (for vinegar fermentation), Bacteria can be used in treating and
whereby ethanol is partially oxidised into purification of water or sewage in
ethanoic acid (vinegar). oxidation pond, by reducing the bulky of
wastes and converting them into simpler
(b) Manufacturing of dairy products forms that can be easily handled in the
In this case, bacteria such as Streptococcus subsequent stages in a stabilisation ponds
lactis are employed in preparation and (lagoon). Examples of decomposers
preservation of commercial butter, cultured include Streptomyces sp. and Bacillus sp.
milk, and cheese from cream milk. The
bacteria species Streptococcus thermophilus (f) Making flavour, aroma and curing
and Lactobacillus bulgaricus are frequently of agricultural products
used in preparation of yoghurt by inoculating Bacteria are used for production of different
fresh milk with a starter culture containing dairy flavour compounds, such as butyric
Brevibacterium linens in order to produce acid, lactic acid and diacetyl in mixed
the appealing smell in cheese.
cultures of Lactobacillus acidophilus and
Pediococcus pentosaceus. Some bacteria
(c) Manufacturing of amino acids,
proteins, and starch such as Bacillus subtilis have been used to
In the manufacture of amino acids, some bring about several physio-chemicals and
bacteria such as Monococcus glutamis are sensory changes in soybean foods to make
used. Industrial proteins such as amylase it highly digestible and nutritious. Bacillus
are produced by bacteria such as Bacillus subtilis, which dominates traditionally
polymysa. fermented soy foods have typical taste,
texture and aroma, which is popular in

(d) Decomposition of organic matters Asian and African countries. Certain
Most bacteria are chemoheterotrophs, bacteria such as Bacillus megaterium
which obtain their food from dead or can be used in curing off the bitterness in
decaying organic matter. In so doing, such leaves of tea and tobacco.
bacteria reduce heaps of dead substrates

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