chloroflexus & spirullina
TRANSCRIPT
GROUP MEMBERSNATIONAL UNIVERSITY OF SCIE & TECH
ZIMBABWE
Lazarus Mavima
Joseph Ndondo
Yeukai Muusha
Tatenda Marumbwa
Faith Ntokozo
Cain Kaundikiza
Irvine Mpofu
CHLOROFLEXUS&
SPIRULINA
BACKGROUND
• Chloroflexus are genus of bacteria also called the green non
sulphur bacteria.
• They are classified as thermophiles.
• They are photosynthetic bacteria but differ from
cyanobacteria and eukaryotes in that…….
CHLOROFLEXUS SPP CONT…
they are anoxygenic, do not have photosystem ll, hence
cannot use water as an eletron donor in noncyclic electron
transport
they use electron donors such as hydrogen, hydrogen
sulphide, organic compoucnds
they do not possess chlorophyll but possess slightly
different photosynthetic pigments or bacteriochlorophylls
i.e. bacteriochlorophyll a and c
• Chloroflexus spp. are gram negative filamentous
thermophilic bacteria
• often isolated from neutral to alkaline (pH 9) hot spring
• Chloroflexus show photosynthetic properties characteristic
of both purple bacteria and green bacteria.
• Chloroflexus is found at higher temperatures with an optimal
growth between 50 and 55oC
• Generally, Chloroflexus inhabit a number of environment
types such as hot springs, lakes, river water and sediments,
and in marine and hypersaline environments. Near hot
springs, especially.
• Freshwater lakes also contain Chloroflexus-like organisms
• Some strains of Chloroflexus can also grow alone in springs
high in sulfide, which it uses as an electron donor
• Sulphur produced by sulphide oxidation is deposited
extracellularly.
• an example of such bacterium is Chloroflexus aurantiacus
ENVIRONMENTS WHERE ANAEROBIC THERMOPHILES CAN BE ISOLATED
Terrestrial hot springs at Viterbo Italy (Left) & The hot pool of
Bagno Vignoni, Italy.
• Chloroflexus can be found in the lower layers of microbial
mats with cyanobacteria growing above it.
• It seems to use the organic products of the cyanobacteria;
however,
• some strains Chloroflexus can also grow alone in springs
high in sulfide, which it uses as an electron donor (it can
also use hydrogen).
CELL STRUCTURE AND METABOLISM
• Chloroflexus is a, filamentous, gliding bacterium found in
the green non-sulfur branch in the 16s rRNA tree of life.
• They lack internal membranes unlike unlike purple
bacteria
• Generally, Chloroflexus is a photoheterotroph and uses
organic molecules that are made from other bacteria, but
some Chloroflexus strains grow autotrophically and use
hydrogen or sulfide as an electron donor.
NUTRITION AND METABOLISM
• Chloroflexus shares with green bacteria the ability to grow
photoautotrophically using sulfide as electron donor
• it does so employing a unique pathway for autotrophic CO2
fixation, the hydroxypropionate pathway. This pathway is
absent from all other anoxygenic phototrophic bacteria.
• Chloroflexus aurantiacus fix CO2 differently from other
phototrophs through a pathway called the 3-
hydroxypropionate pathway
• They seem to lack ribulose bisphosphate carboxylase
activity
• In anaerobic (or semiaerobic) situations, Chloroflexus
aurantiacus harvests light in chlorosomes that are slightly
smaller than those of green sulfur bacteria. Also like purple
bacteria, Chloroflexus bacteria have pheophytin-quione type
photochemical reaction centers. (Sprague et al. 1981)
• Aerobically chloroflexus aurantiacus do not produce
bacteriochlorophylls and grows chemotrophically
SPIRULINA SP.
• Spirulina were initially thought to be eukaryotes (a
type of fungi)
• However, phylogenetic and morphological analysis
illustrated them to be bacteria.
• Many genera of cyanobacteria are harmful to
humans. Spirulina, however, are unique not only in
that they are edible, but also because they provide
many health benefits.
• Spirulina are Gram-negative, microbes that are
undifferentiated and filamentous.
• Spirulina can be rod shaped bacilli or disk-shaped.
• Their main photosynthetic pigment is phycocyanin,
which is blue in color, along with chlorophyll a and
carotenoids.
• Some contain the pigment phycoythrin, giving the
bacteria a red or pink color.
• Spirulina have gas vesicles, giving them bouyancy in
the aquatic environments they inhabit. Spirulina are
photosynthetic, and therefore autotrophic bacteria
that reproduce by binary fission.
• Spirlulina are aquatic organisms, typically inhabiting
freshwater alkaline lakes and marine bodies.
• They are mesophilic, and able to survive over a wide
range of temperatures
• Spriulina is an edible bacteria. Flamingos get their pink
color from eating Spirulina that contain phycoythrin .
• It is also used in Asian cusine. In America, Spirulina is sold
in health food stores as a powder or tablet (Spirulina are
an excellent source of both protein and iron).
• Its carotenoids absorb radiation.
• Evidence shows that it is capable of stopping viral
replication. It prevents the virus from penetrating a
cell wall and infecting the cell.
• This bacteria also slows neurological damage in aging
animals, and it can lessen the damage caused by
stroke.
• Studies also show that Spirulina can prevent the
release of histamines, treating allergy symptoms.
• Spriulina has nonmedical uses as well. A study by
Chen and Pan (2005) shows that the bacteria can
remove low concentrations of lead from wastewater