• Colorless cells.
• ~1-50um x ~2-10um.
• Cells are disk shaped, typically wider than they are long.
• May exist as single cells or in filaments up 50 cells.
• Filaments can occur singly or in cottony masses.
• Reproduce by transverse binary fission.
• Cells contain sulfur inclusions when grown in presence of hydrogen sulfide.
• Inclusions of Poly-B-hydroxybutyric acid or polyphosphate may be present.
• Stain Gram negative.
• Cells and Filaments are motile by gliding, no motility organelles know.
• Aerobic or microaerophilic.
• The percent G+C ranges from 37-51%
• Growth occurs between 0-40 degrees Celsius.
• Chemoorganotrophic and facultatively autotrophic.
• Oxidase positive.
• Catalase negative.
• Resting stages are unknown.
  
  The above left image is of Beggiatoal mat.
  

2. TAXONOMIC DESCRIPTION

Most species of Beggiatoa produce sulfur granules when grown in the presence of hydrogen sulfide or thiosulfate. Also inclusions of Poly-B-hydroxybutryic acid and polyphosphate, for carbon and phosphorus storage respectively. The cells and filaments are motile through gliding. The Gliding is usually rapid (1-8um/s-1). The gliding motility usually determines the type of growth and colony formation.

Metabolism is aerobic or microaerophilic with oxygen as the terminal electron acceptor in respiration. Sulfur may substitute as the terminal electron acceptor for a short period in the absence of oxygen. The substitution of sulfur in for oxygen is usually thought to be used while the bacteria glide to a new area where oxygen can be acquired. Several species fix dinitrogen. Nitrate, nitrite, ammonium, dinitrogen and certain amino acids as nitrogen sources. Beggiatoa are chemoorganotrophic and faculatively autotrophic.

The above picture of shows Beggiatoa accumulating sulfur granules.

Beggiatoa is able to be cultivated easily in low nutrient mediums. As long as ample amounts or sulfur compounds are supplied for oxidation. No known growth factors are known to be required for Beggiatoa strains with the exception of B12 that is needed for a few species. Low levels of organic and nitrogenous compounds provide a better growth environment with longer cell viability.

Beggiatoa can usually be found in habitats that have high levels of hydrogen sulfate. These environments include sulfur springs, sewage contaminated water, mud layers of lakes, also near deep hydrothermal vents. Also Beggiatoa can be found in the rhizosphere of swamp plants. The key to Beggiatoa growth since it is a gradient organism is its placement. It thrives best when acquiring sulfide diffusing up from below and oxygen diffusing down from above. In marine environments Beggiatoa form filaments that twine together to form mats, these mats aid in capturing the sulfides and oxygen.

The above image is of a dried beggiatoa colony.

4. ADDITIONAL SOURCES OF INFORMATION

5. LINKS TO OTHER SITES ON Beggiatoa