University Of Zakho
Faculty Of Science
Department Of Biology
Home work
{ Phycology }
Prepared by: Hoshmand Hersh Sabr
2022 – 2023
USEFUL ASPECTS OF ALGAE
1. Algae as human food:
a) Chlorella, a unicellular green alga, possesses a high quality of food value.
b) It has about 50 % proteins and 20% lipids and carbohydrates. Besides, it
contains vitamins A, B, C, K and essential amino acids.
c) Porphyra tenera (a red alga) is known as Amanori in Japan and the
preparation is known as Asakusa Nori.
d) Laminaria (a brown alga) yields a food product known as kombu or konbu
e) Young stipes of Laminaria are eaten directly in certain parts of Europe
and America.
f) Nostoc ( blue green alga) balls of terrestrial species are collected, boiled
and consumed as food by the Chinese.
g) Alaria (a brown alga) yields a product known as Sarumen in Japan.
h) Monostroma (a green alga) yields food product Aonori in Japan.
i) Ulva lactuca(a green alga) used in salad and soups.
j) Rhodymenia palmate (a red alga) used as food and also as confectionary
named dulse.
2) Nitrogen Fixation: The conversion of atmosphere nitrogen compounds is
one of the major roles being played by the algal plants especially by the
members of Cyanophyta (blue-green algae). A high rice yield has obtained
when the rice fields were inoculated by certain nitrogen-fixating blue-green
algae.
3) Fertilizers: Due to presence of phosphorous, potassium, calcium and some
traces elements, the sea weeds (brown algae) are used as fertilizers in most
of the coastal countries of the world. For example Chara is used to overcome
calcium deficiency in the fields, and Fucus is used as common manure.
4) Algae used as fodder: Sea weeds, such as Fucus, Laminaria, Sargassum,
Ascophyllum etc. are used as fodder for the sheep, goat, cattle and poultry in
many countries.
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5) Antibiotics and Medicines: Some algae yield antibiotics, e.g., Chlorellin is
obtained from green alga Chlorella; that inhabits the growth of certain
bacteria. Similarly some species of Polysiphonia produce antibacterial
substances which are effective against gram-negative and gram-positive
bacteria. An antibiotic is obtained from a diatom Nitzschia palea which is
effective against Escherichia coli. Because of high iodine contents, brown
algae are used in manufacture of various goiter medicines.
6) Role as Primary Producers: Because of their photosynthetic abilities the
algae are the primary producers of the aquatic environments. They provide
food and energy to the animal life, produce oxygen and take up carbon
dioxide produced during respiration which is injurious for living organisms
especially fishes.
7) Algae in space research: Unicellular alga chlorella or Scenedesmus could
be used to provide oxygen during space flights.
8) Soil formation : algae growing symbiotically with lichen acts as pioneers of
succession on barren rocks and help in soil formation.
9) Commercial products of algae:
i) Agar-agar: Extracted from red algae, particularly, Gelidium,
Gracilaria, Gigartina, Pterocladia, Chondrus, Ceramium etc.
ii) Alginates :Obtained from Macrocystis, Ascophyllum, Laminaria,
Fucus, etc. in India it is obtained from Sargassum. used in the
preparation of creams, jellys, soups , sauces and ice-creams because of
its nontoxic nature.
iii) Iodine : obtained from Laminaria, Fucus, and Macrocystis pyrifera
(giant kelp).
iv) Bromine: obtained from Rhodomella and Polysiphonia.
v) Carrageenin: it is found in the cell wall of red algae. It is mainly
obtained from Chondrus crispus .
vi) Diatomite (Kieselgurh): Big deposits of fossilized diatoms in the
sedimentary rocks make diatomaceous earth or diatomite. These
deposits are mined as diatomaceous Earth. Used in industrial
filtrations, preparation of high temperature furnaces, as insulators in
refrigerators, polishes of metals etc.
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