Biosynthesis of Photosynthetic Pigments and Applications

Biosynthesis of different
photosynthetic pigments
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APPLICATIONS
BY GROUP 4
Photosynthetic pigments
• These occur as complexes bound with associated
proteins.
• The pigment consist of chromophores."greek
means carrier of color"
• Examples
• Chlorophyll
• Carotenoids
• Phycobilins
• Flavonoids
Spectrum
Carotenoids biosynthesis
Carotenoid biosynthesis
• , the pigments responsible for the vibrant red,
orange, and yellow colors in many fruits,
vegetables, and flowers, are also synthesized
through a fascinating biological pathway. Similar to
chlorophyll, carotenoid biosynthesis occurs within
specific cellular compartments called plastids, with
plants and some microorganisms sharing a similar
pathway. Here's a breakdown of the key steps:
• Formation of Isopentenyl diphosphate (IPP) and
Dimethylallyl diphosphate (DMAPP): These five-
carbon molecule precursors serve as the building
blocks for carotenoids and are derived from either
the mevalonate (MVA) pathway or the
methylerythritol phosphate (MEP) pathway.
.
• Condensation and Formation of Phytoene: Two
molecules of DMAPP condense with a molecule of
IPP, catalyzed by the enzyme phytoene synthase
(PSY), to form phytoene, a colorless C40
carotenoid. This reaction is considered the first
committed step in the pathway, meaning the
precursors cannot be readily converted into other
molecules.
•.
• Desaturation and Isomerization: Phytoene
undergoes a series of modifications involving
enzymes like desaturases and isomerases. These
enzymes introduce double bonds and rearrange
existing ones, transforming phytoene into various
intermediate carotenoids with increasing levels of
conjugation (alternating single and double bonds),
leading to a gradual yellowing of the molecule
• Cyclization and Formation of α-Carotene and β-
Carotene: At the lycopene stage, the pathway
branches. One branch involves the enzyme β-
cyclase (β-CYC), which cyclizes the ends of the
lycopene molecule to form β-carotene, the most
abundant carotenoid in plants and a precursor to
vitamin A.
• Formation of Xanthophylls: The other branch
involves the enzyme ε-cyclase (ε-CYC), which
cyclizes one end of the lycopene molecule to form
α-carotene. α-Carotene can then be further
modified by enzymes like hydroxylases and
epoxidases to form various xanthophylls, such as
lutein and zeaxanthin. These oxygenated
carotenoids exhibit a wider range of colors,
including yellow, orange, and red.
Phycobilins
• Phycobilins are light-harvesting pigments found in

cyanobacteria, red algae, and cryptophytes. They
are responsible for the blue-green and red colors of
these organisms and play a crucial role in
photosynthesis by capturing light energy and
transferring it to chlorophyll a, the primary reaction
center pigment in these organisms.
Accessory role
• Efficient Absorption: Phycobilins efficiently absorb
light in the red, orange, yellow, and green
wavelengths—ranges that are not as well absorbed
by chlorophyll a. Their presence allows organisms
to capture light that chlorophyll alone might miss
Phycobilin biosynthesis
• The biosynthetic pathway of phycobilins. Bilin
synthesis starts from the cleavage of heme b (bilin
b) by hemeoxygenase (HO) to yield biliverdin IXα,
the central molecule of bilin biosysnthesis
pathways.
• Biliverdin IXα is further reduced by either NAD(P)H-
or ferredoxin-dependent bilin reductases (FDBR)
FDBR reductase like PebA synthase and PebB
synthase transfer two electrons to their substrate to
give phycoerythrobilin in two step catalysis.
PcyA and PebS catalyze the transfer of four electrons
from ferredoxin to two distinct double bonds of
biliverdin to yield phycocyanobilin and
phycoerythrobilin, respectively in single step.
Phycocyanobilin and phycoerythrobilin are further
reduced to phycoviobilin and phycourobilin,
respectively by PecE/F of Rpc G reductase
• Complex but can be summarized into a three step
pathway
1. Formation of the precursor biliverdin IXa: This
step starts with the breakdown of heme. The
enzyme heme oxygenase (HO) cleaves the heme
molecule, releasing biliverdin IXa and carbon
monoxide.
2. Conversion of biliverdin IXa to specific phycobilins:
Biliverdin IXa serves as the starting point for the
synthesis of various phycobilins. Different enzymes
act on biliverdin IXa, introducing specific
modifications that result in the formation of different
phycobilins. These enzymes are collectively known as
ferredoxin-dependent bilin reductases (FDBRs).
3. Attachment of phycobilins to protein scaffolds:
The final step involves covalently linking the
synthesized phycobilins to specific cysteine residues
on protein scaffolds called phycobiliproteins. This
linkage is established through a thioether bond
formation by bilin lyases.
• The specific type of phyco bilin produced depends on
the action of different FDBRs. Some of the common
phycobilins include:
• Phycocyanobilin (PCB): Blue-green pigment
• Phycoerythrobilin (PEB): Red pigment
• Allophycocyanin (APC): Blue pigment
• These phycobilins are arranged in specific
phycobilisome structures, which efficiently transfer the
captured light energy to chlorophyll a within the
photosystems of cyanobacteria, red algae, and
cryptophytes.
Applications of photosynthetic
pigments
• Medical applications
• Nutritional applications
• Energy production applications
• Environment applications
Medical applications
• Blood building properties
Chlorophyll is chemically similar to hemoglobin, a protein essential
for carrying blood. Research suggests that a glass full of wheatgrass
juice which is rich in chlorophyll is helpful in treatment of hemoglobin
disorders such as anemia and thalassemia.
• Cancer treatment
Plant pigments such as chlorophyll and carotenoids have anti cancer
effects.
These obstruct cancer cell proliferation, stop growth and cell division
in cancer cells.
They also inhibit cellular processes in cancer cells such as signaling
pathways, cell cycles, induce apoptosis and autophagy.
Nutritional enhancement
Energy production
• Bio fuels
Photosynthetic pigments can be used in the
production of bio fuels, algae rich in pigments are
being explored as a source of bio fuels due to their
rapid growth and high lipid content. Eg
1. Biodiesel
2. Bioethanol
3. Biogas
4. Bio hydrogen
Environmental
• Bio remediation
This is a process that uses living organisms, such as
plants, bacteria and fungi, or algae, to remove or
neutralize contaminants from polluted environments.
1. Phytoremediation
2. Algal bioremediation
Liquid tree
• Liquid trees represent a biotechnological innovation
that has been developed by scientists in Serbia to
tackle air pollution. The liquid tree structure
consists of a 600-liter water tank filled with
microalgae, which bind with carbon dioxide in the
environment through photosynthesis, converting
it into oxygen.
Application of photosynthetic
pigments
• Chlorophyll popular way to get chlorophyll into the
diet is through taking supplements. These are
available in the form of drops, pills, or capsules.
Most chlorophyll supplements contain
chlorophyllin. Chlorophyllin is a water-soluble
derivative of natural chlorophyll that is potentially
better absorbed by the body than other forms of
chlorophyll.
Benefits
Anti-aging remedy
Topical chlorophyll may work as an anti-aging
remedy. applying a gel containing chlorophyllin to
the skin reduced signs of photoaging, which is aging
that results from sun exposure.
Acne treatment Topical: chlorophyll may also have
potential as an acne treatment. reduce facial acne
and large, visible pores.

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Biosynthesis of different

• Phycobilins are light-harvesting pigments found in

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