Category: Biology Second Paper Lecture Sheet

A group of researchers from Dhaka University and Sweden’s Uppsala University have made nano filters from Pithophora algae. Nano filters are cellulose filters. It is like white paper and the pores of the filters are 17 nanometers. Waterborne microbes are 30-100 nanometers. So all viruses and bacteria are trapped in the filter. It is possible to separate toxic arsenic, ions, salts etc. from water.

Algae like Nostoc, Anabaena, Aulosira etc. have heterocysts. Heterocysts fix nitrogen. These algae convert nitrogen into usable ammonia.

Different types of algae are used as fish food. So algae are used in ponds or reservoirs for fish farming. Several types of algae are used as feed in tilapia fish farming.

Agar-agar is made from marine red algae (Gelidium, Gracilaria, Gigartina). It is used in the preparation of several types of food.

(i) Alum, glass, soda, potash, alginic acid and soap are made from seaweed kelp.
(ii) Ice-creams, jellies, paints, varnishes, shampoos and cosmetics are made from olgin of brown algae and gelatin of red algae.
(iii) Soap, paper, photography, rayon etc. are made from algae agar.
(iv) Polymers like starch and polyhydroxy-alkanoates are formed naturally in algae. Bioplastics are made from all these polymers.
(v) Carrageenan from algae (Chondrus crispus) is used in food processing, rayon, pharmaceutical industry, leather industry, toothpaste and dyes.
(vi) Algae (Furcellaria) furcellaran is used in making jam-jelly, preserving fish and meat and in toothpaste and pharmaceutical industry.
(vii) Algae (Gleopeltis furcata) is used in pulp and paper industry and for making glue.
(viii) Iodine and potash are produced from Laminaria algae.

Chlorella is used in space research to purify the polluted air of spacecraft. Chlorella fulfills the oxygen demand in space.

Agar agar is made from Gelidium, Gracilaria, Pterocladia etc., Goiter medicine is made from Sargassum and Laminaria and Chloreline antibiotic is made from Chlorella. Galactans are produced from the red algae Callophyllis variegate and Agardhiella tenera. Galactans are used to prevent HIV. Oral cancer drugs are made from algae containing beta-carotene, which has antioxidant properties.

Diatomaceous (Navicula) algae bodies accumulate at the bottom of water bodies to form diatomaceous earth or diatomite. Soil age is determined by carbon dating the shells of diatoms deposited in the soil layer. Diatomite is used to make water filters, boilers, blast furnaces, metal polishes, toothpastes, etc. Diatomaceous earth was used to make dynamite.

Seaweed is used as a source of potash fertilizer. Such as Spirulina, Scytonema, Oscillatoria, Anabaena, Nostoc etc.
10. Determining the location of spy submarines: Blue-green algae contain pigment particles called phycobilin protein. These pigment particles (C-phycoerythrin, C-phycocyanin) absorb the diffracted rays from spy submarines. The location of the spy submarine is determined by the amount of absorbed radiation.

Biofuel or Biodiesel is made from algae. So algae are called second generation biofuels. Botryococcus braunii algae is being used to make biofuel. Attempts are being made to produce biofuel from Chlorella and Scenedesmus algae. Recently, researchers are trying to produce third generation biofuels from microalgal biomass. Some micro-algal species Kirchneriella lunaris, Ankistrodesmus fusiformis, Ankistrodesmus falcatus, Chlamydocapsa bacillus, Chlorella, Scenedesmus etc. have been taken for biodiesel production.