What is it??• Purple sulfur bacteria from the family of chromatiaceae• T.roseopersicina was discovered by Sergei Winogradsky in the 1880s when he was studying sulfur bacteria• Gram negative bacteria• Non-motile bacteria
• Either rose colored or milky white• Rose colored formed by the optical activity of the carotenoids(pigments of chloroplast)
Where it can be found??• T. roseopersicina is mainly found in microbial mats in hypersaline and marine environments• T. roseopersicina has often been found in anaerobic waste stabilization ponds that have a lot of dissolved organic matter• T.roseopersicina grown in the light under anaerobic conditions and in the darkness under aerobic conditions
Cell metabolism• T. roseopersicina has two different types of metabolism that it can use based on the environment• Its main metabolism is anaerobic photosynthesis which uses reduced sulfur compounds as electron donors. The secondary metabolism is chemolithotrophy in dark environments,• When T. roseopersicina is using its photosynthetic metabolism, it has a faster growing rate.
• When T. roseopersicina is growing under chemolithotropic conditions, it has to compete with colorless sulfur bacteria.• The bacterium reaches a stationary phase at 3- 4 days with the photosynthetic conditions whereas it reaches a stationary phase at 7-12 days with the chemolithotrophic conditions.
Structure• T. roseopersicina has spherical cells that can form tetrads. The cells are 1-3µm in size.• The cells do not have gas vesicles.• T. roseopersicina can use hydrogen, sulfide, thiosulfate, acetate, propion ate, pyruvate, malate, succinate, fumarate, fruc tose, or glycerol as substrates.• It cannot use formate or glucose as substrates though
Anoxygenic photosynthetic bacteria??• Anoxygenic photosynthesis is the phototrophic process where light energy is captured and stored as ATP, without the production of oxygen.• This means water is not used as primary electron donor.• There are three groups of bacteria that undergo anoxygenic photosynthesis: phototrophic green bacteria, phototrophic purple bacteria, and heliobacteria.
The environment• T. roseopersicina has optimal growth in a medium with 0.3 M sodium chloride• This is a lower concentration than that of the seawater that T. roseopersicina is found, but that is common for marine/halotolerant organisms to have different optimal conditions than that of the environment they are isolated from• This is a good survival technique as the osmolarity of the marine water fluctuates from various occurrences like rain or evaporation
The colour is due to purple sulphur bacteria which growwhen there’s an abundance of plant debris in the bottom ofthe pond, producing a lot of hydrogen sulphide gas (thesmell of rotten eggs). Purple bacteria use hydrogensulphide instead of water to power their photosynthesis.
• Pink ponds may be the result of a perfectly natural build up of plant debris or the result of pollution by rotting organic matter or sewage.• So being pink doesn’t automatically mean your pond is polluted – but it does mean it has a lot of organic matter.
Its functionT. roseopersicina can fix atmospheric N2• This process is usually accompanied by Hydrogen production• T. roseopersicina has three different Nickel Iron hydrogenases(catalyzes Hydrogen generation and Hydrogen oxidation)• Hydrogen oxidation is important for fuel cells
How to culture• It is anaerobes bacteria• Anaerobes can inoculated in an agar slant using an inoculating needle• Needle is able to put the anaerobes deep inside the agar.• The anaerob can grow in the anaerobic environment provided.• The agar slant should then be refrigerated after suitable growth is achieved
Application to biotechnology• T. roseopersicina is an important bacterium for microbial detoxification• It is one of the few bacteria that can completely oxidize dimethyl sulfide (DMS) to sulfate