BIOSORPTION OF Pb2+, Cd2+, & Ni2+ FROM WATERS BY ...

1.5.2. Oocystis sp.
Oocystis sp. is a green microalgae having unicells or colonies of non-fixed
number of cells, and the shape of cell body is variable. The shape of one or more
chloroplasts is subjected to change. Autospore or autocoenobium provides asexual
reproduction. Colony of 2-8 cells is encircled by cell wall of their mother cell,
however, it is sometimes unicellular . It has a broad ellipsoidal cell body (Protist
Information Server 2008).
1.5.3. Porphyridium cruentum
Porphyridium cruentum, the unicellular red alga with spherical cells lacking a
cell wall, is a primitive member of the Rhodophyta, order of Porphyridiales. The
diameter of cells ranges from 4 to 9 µm.The cells can live in theirselves or in the form
of colonies. The wall-less cells, including a single large chloroplast, which are
surrounded by a cover of a water-soluble sulphated polysaccharide. Due to the
polysaccharide enveloping the algal cells from the environment, Porphyridium can
survive under extreme environmental conditions (Arad and Ucko 1989) and it can
found in sea water and in humid soils.
From the economical point of view, the useful products of Porphyridium such
as sulphated polysaccharides and a red proteinaceous pigment as phycoerythrin are
obtained possibly. Owing to the production of eicosapentaenoic acid and other
polysaturated fatty acids, Porphyridium cruentum has come the industrial interest
(Banerjee 2005).
1.5.4. Scenedesmus protuberans
Scenedesmus protuberans is a small, nonmotile colonial green alga including
of cells arranged linearly or zigzag in a flat plate. The colonies usually have two or
four cells, but may have 8, 16, or seldom 32 and are sometimes unicellular The cells
are generally shaped as cylinder, however might be more lunate, ovoid, or fusiform.
In a tyical manner, the end cells each have two flagellates from their outer corners
Each cell consists of a single parietal, plate-like chloroplast with a single pyrenoid.
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