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