Oxygenic Photogranules (OPGs) are a type of biological aggregate with a spherical shape, usually from a millimeter to centimeter scale. OPG is characterized by layers of fabric such as phototropic organisms, large principled cyanobacteria of oscillatorial orders. The production of oxygen by these phototrophs through photosynthesis is usually combined with oxygen consumption from heterotrophic biomass, releasing CO 2 which may be used in syntrophic relationships by autotrophic phototrophs.
Video Oxygenic photogranules
Discovery/Context
In 2011, Park and Dolan first observed active sludge transformation into oxygenic photogranules (OPG), when incubated in un-agitated and sealed bottles exposed to natural light for several months. Since then, this static OPG cultivation is observed with active sludge originating from different parts of the world in several laboratories [3], [4], [5], [6], [7] etc.) OPG was recently discovered and by chance in laboratory conditions, but very similar granules, called cryoconites, are found in glaciers.
Maps Oxygenic photogranules
Oxygenic photogranul formation
The formation of anaerobic and aerobic granules is usually postulated to be driven by shear hydrodynamics and washout. Oxygenic phototranules are formed when exposed to shear hydrodynamics in batch sequencing reactors; however, they are also formed under a static batch & amp; . They can be formed for several weeks from the source of activated sludge exposed to light. How the forms of oxygen photogranules are far from understood, but filament and motile cyanobacteria seem to play an important role in their formation. Cyanobacteria are enriched from activated sludge and form an outer layer of photogranules that provide structural integrity for both photogranules produced under hydrodynamic and static conditions. This hypothesis is supported by the finding that the early presence of inorganic nitrogen in active sludge inoculum promotes cyanobacterial growth of microalgae growth, resulting in successful oxygenic photogranules. The formation of oxygenic photogranules is thus not driven by the shear hydrodynamic and washout not required for the formation of oxygenic photogranules, although these factors may play an important role when applied. Filamentous, motile cyanobacteria play a key role, but the exact mechanism must be explained to be able to control the formation and properties of oxygenic photogranules and apply them to biotechnological processes.
Oxygenic Photogranes applied to wastewater treatment
Oxygen photogranules are a new type of biogranules that have not been applied in biotechnological processes. but has promising potential to be applied in wastewater treatment. OPG has been applied in reactor batch reactor mixture of SBR turbulent and in high algae ponds. Oxygenic phototranranes have the ability to pair oxygen production through photosynthesis to conversion of organic matter to carbon dioxide by heterotrophs. Therefore, they have the potential to treat wastewater without an external source of aeration and to generate energy when this biodegradable biofeedstock is used for anaerobic digestion.
References
External links
- http://www6.montpellier.inra.fr/narbonne_eng/Research-themes/Photogranules
- http://cee.umass.edu/environmental-water-resources-engineering
- http://www.mhtc.ro/national-research-development-institute-industrialecology
- http://www.iingen.unam.mx/es-mx/BancodeInformacion/Entrevistas/Paginas/GermanBuitronMendez.aspx
- https://www.researchgate.net/profile/Dong-Hoon_Kim
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