Algal Pigments- Structure and Function discusses the various pigments found in algae. It begins by introducing that algae range in size and can be single-celled or multicellular organisms. They contain chloroplasts or chromoplasts in their cells that harbor pigments. The main pigments discussed are chlorophyll a, chlorophyll b, xanthophyll, fucoxanthin, phycocyanin, and phycoerythrin. Each pigment has a unique molecular structure and absorbs different wavelengths of light, allowing algae to capture more of the sun's energy for photosynthesis. The pigments also serve protective functions. In conclusion, the variety of pigments allow different types of algae to

1. Algal Pigments- Structure and
Function
Submitted By
Moumita Paul
Dept. of Life Science
and Bioinformatics

2. INTRODUCTION
 Algae comprises the simplest plants which possess
undifferentiated roots, stem and leaves or thallus
 Range in size from microscopic to single celled
organisms to large seaweed
 Chlorophyll containing autotrophic members of
thallopthyta
 Members of blue-green algae(Cyanophyta) possess
prokaryotic nature of cells, while the remaining algae
to other division possess eukaryotic nature of cells
 Plastids(chloroplast or chromoplasts) are present in
the cytoplasm of each cell.
 One or more specialized bodies called pyrenoids
which consists of colourless masses of proteins
sourrounded by starch plates

3. ALGAL PIGMENTS
 Pigments are chemical compounds which reflect only certain wavelengths of visible
light. This makes them appear "colourful". Flowers, corals, and even animal skin
contain pigments which give them their colours. More important than their reflection
of light is the ability of pigments to absorb certain wavelengths
 A photosynthetic pigment (accessory pigment; chloroplast pigment; antenna
pigment) is a pigment that is present in chloroplasts of any photosynthetic organisn
and captures the light energy necessary for photosynthesis
 Since each pigment reacts with only a narrow range of the spectrum, there is usually
a need to produce several kinds of pigments, each of a different color, to capture
more of the sun's energy.
 The pigments found in algae are
 Chlorophyll
 Xanthophyll
 Fucoxanthin
 Phycocyanin
 Phycoerythrin

4. CHLOROPHYLL
 Chlorophyll (also chlorophyl) is a green pigment found in
cyanobacteria and the chloroplasts of algae and plants
 Chlorophyll absorbs light most strongly in the blue portion of the
electromagnetic spectrum, followed by the red portion.
 There are different types of Chlorophyll pigment that have been
identified by famous chemists including Richard Willstätter, Hans
Fischer, Robert Burns Woodward and Ian Fleming.
 Their structures are based on a chlorin ring at the center of which is
a magnesium ion
 The structure can have different side chains depending on the
type of Chlorophyll

5. CHOLROPHYLL a
 Chlorophyll a is the most widely occurring and universal type of Chlorophyll.
 Molecular formula - C55H72O5N4Mg
 Chlorophylls are greenish pigments which contain a porphyrin ring.
 Molecular structure consists of a chlorin ring with Mg center.
 The chlorin ring is a heterocyclic compound derived from pyrrole
 Four nitrogen atoms from the chlorin surround and bind the magnesium atom.
 This is a stable ring-shaped molecule around which electrons are free to migrate.
 It also has side chains and a hydrocarbon trail
 Contains only methyl groups (CH3) as side chains
 has a long hydrophobic tail, which anchors the molecule to other hydrophobic
proteins in the thylakoid membrane of the chloroplast.
 It absorbs light from red, blue and violet wavelengths and gets its colour by
reflecting green.

6. Function
 Used in oxygenic photosynthesis
 This photosynthetic pigment is
essential for photosynthesis in
eukaryotes, cyanobacteria and
prochlorophytes because of its
role as primary electron donor in
the electron transport chain .
 Chlorophyll a also transfers
resonance energy in the antenna
complex, ending in the
reactioncenter where specific
chlorophylls P680 and P700 are
located
 Within the reaction centers of
both photosystems there are a
pair of chlorophyll a molecules
that pass electrons on to the
transport chain through redox
reactions

7. Chlorophyll b
 A second kind of chlorophyll is chlorophyll
"b", which occurs only in "green algae’’ and
in the plants.
 Chlorophyll b absorbs most effectively at
blue 470 but also at 430 and 640
 Molecular formula - C55H70O6N4Mg
 It is an accessory photosynthetic pigment
 Molecular structure consists of a chlorin
ring with Mg center
 The chlorin ring is a heterocyclic compound
derived from pyrrole
 Four nitrogen atoms from the chlorin
surround and bind the magnesium atom
 also has side chains and a hydrocarbon
(phytol) tail
 Pyrrole ring II contains an aldehyde group (-
CHO)

8. Function
 Absorb energy that chlorophyll a does not
absorb
 Functions as a Light-harvesting Antenna in
Photosystem I

9. XANTHOPHYLL
 Xanthophyll are yellow pigments that form one of
two major groups of the carotenoids group
 It is generally a C40 terpenoid compounds formed
by condensation isoprene units
 xanthophylls contain oxygen atoms
 Xanthophylls contain their oxygen either as
hydroxyl groups and/or as pairs of hydrogen atoms
that are substituted by oxygen atoms acting as a
bridge (epoxide)

10. FUNCTION
Xanthophyll acts as an accessory light harvesting pigment
Have critical structural and functional role in the photo
synthesis of plants and algae
Also serve to absorb and dissipate excess light energy,
Or work as antioxidants
Xanthophyll may be involved in inhibiting lipid
peroxidation

11. FUCOXANTHIN
 Fucoxanthin is a carotenoid, which performs a
limited form of photosynthesis in Brown Algae
(Phaeophytes). and other heterokonts.
 It is responsible for the brown or olive-green
colour of these algae.
 Molecular formula C42H58O6
 Fucoxanthin absorbs red light to perform
photosynthesis
 The pigment is produced in abundant quantities
by the following edible brown algae : Laminalia
japonica, Undaria pinnatifida , Sargassum
fulvellum etc
 It is a xanthophyll — an oxygenated carotene, or
plant pigment

12. FUNCTION
 It is a xanthophyll — an oxygenated carotene, or plant pigment
 Brown algae is an abundant class of plants, with most species living in
the ocean and employing fucoxanthin for photosynthesis
 The substance is sensitive to shorter wavelengths of light, so most
brown algae live in shallow water
 It is the main carotenoid produced in brown algae as a component of
the laight harvesting complex for photosynthesis and photoprotections
 fucoxanthin as an anti-obesity substance

13. PHYCOCYANIN
 Phycocyanin is a pigment-protein complex from the light-
harvesting phycobiliprotein family, along with allophycocyanin
and phycoerythrin
 It is an accessory pigment to chlorophyll
 Water-soluble, so they cannot exist within the membrane like
carotenoids
 Phycocyanin is a characteristic light blue color, absorbing
orange and red light, particularly near 620 nm (depending on
which specific type it is), and emits fluorescence at about
650 nm (also depending on which type it is).
 Phycocyanins are found in Cyanobacteria (previously called
blue-green algae).
 The most important pigment in Spirulina

14. FUNCTIO
N
 Phycocyanin (Pc) is a phycobiliprotein that has been recently
reported to exhibit a variety of pharmacological properties. In
this regard, antioxidant, anti-inflammatory, neuroprotective
and hepatoprotective effects have been experimentally
attributed to Pc
 it reduces carbon tetrachloride (CCl(4))-induced lipid
peroxidation in vivo.
 Phycocyanin is related to the human pigment bilirubin, which
is important to healthy liver function and digestion of amino
acids. It imparts its anticancer property to Spirulina.
 Help in curing anemia

15. PHYCOERYTHRIN
 Phycoerythrin(PE) is a red protein-pigment complex from
the light-harvesting phycobiliprotein family, present in red
algae and cryptophytes , accessory to the main chlorophyll
pigments responsible for photosynthesis.
 it is composed of a protein part covalently binding
chromophores called phycobilins. In the phycoerythrin family,
the most known phycobilins are: phycoerythrobilin, the typical
phycoerythrin acceptor chromophore, and sometimes
phycourobilin
 Phycoerythrins are composed of (αβ) monomers, usually
organised in a disk-shaped trimer (αβ)3 or hexamer (αβ)6
 In red algae they are anchored to the stromal side of
thylakoid membranes of chloroplasts, whereas in
cryptophytes phycobilisomes are reduced and are densely
packed inside the lumen of thylakoids.

16.  Phycoerythrin is an
accessory pigment to the
main chlorophyll pigments
responsible for
photosynthesis.
 The light energy is
captured by phycoerythrin
and is then passed on to
the reaction centre
chlorophyll pair, most of
the time via the
phycobiliproteins
phycocyanin and via
allophycocyanin
 R-Phycoerythrin and B-
Phycoerythrin are among
the brightest fluorescent
dyes ever identified
FUNCTION

17. CONCLUSION
 From the above discussion it can be cncluded
that Algae are a major group of photosynthhetic
organism
 In algae pigments are the means by which the
energy the energy of the sunlight is captured for
photosynthesis
 There are various group of algae and can be
classified from one another by the presence of the
photosynthetic pigments
 The photosynthetic pigments are- chlorophyll a ,
chlorophyll b, xanthophyll, fucoxanthin,
phycoerythrin,
 The pigments have wide range of function starting
from photosynthesis to photoprotective activity

18. REFERENCES
 Mitra,D.,Guha,J.,Chowdhuri,S.K.2009.Studies in
Botany.Vol(I).2nd ed.Moulik Library,Calcutta
 Kumar,P. and Mina,U.2013.Life Sciences
Fundamentals and Practice.Vol(II).3rd
ed.Pathfinder Publication,New Delhi
 http://educationportal.com/academy/lesson/chlorophyll
-in-plants-benefits-function-definition.html#lesson
 www.majordifferences.com/2013/05/difference-
between-chlorophyll-and.html
 www.oilgae.com/algae/cla/chl/chl.html
 http://www.oilgae.com/non_fuel_products/betacaroten
e.html

19. THANK YOU 