Chlorobium is a rod-shaped, oval or arc-shaped bacterium that reproduces by binary division and does not move. Studies have shown that Chlorobium is a gram-negative bacteria. Bacterial cells contain bacteriochlorophyll c or d as the main bacteriochlorophyll component. All of these chlorophyll and group 5 carotenoids are located in long oval sacs. These sacs are beneath the cytoplasmic membrane and adhere to the membrane. Bacterial cells do not contain air bubbles.
Chlorobium belongs to anaerobic bacteria according to the degree of oxygen requirement. In the presence of hydrogen sulfide, photosynthesis can take place. They then produce spherical elemental sulfur as an intermediate oxidation product and precipitate in the extracellular medium. Molecular hydrogen can be used as an electron donor. During photosynthesis, molecular oxygen is not released. Due to the presence of photosynthetic pigments, the cell suspensions exhibit various shades of yellow-green and chocolate-brown.
The cells of Chlorobium limicola are rod-shaped and sometimes slightly curved. The cells are 0.7-1.1 microns wide and 0.9-1.5 microns long, and some individuals will be longer. Cells are often linked into chains similar to those of Streptococcus. Some strains produce mucus depending on the culture conditions. The color of individual cells is light green, and the color of cell suspensions is green.
Figure 1. The Immunofluorescence of Chlorobium limicola. (A D Cahill, et al.;1995)
Chlorobium limicola is obligately photoautotrophic and strictly anaerobic. Growth may require vitamin B12. Optimum growth pH range: 6.0-7.0. The optimum pH is 6.8. Optimum growth temperature: 25°-30°C. Electron donors for photosynthesis: sulfide, sulfur. In the presence of sulfide and bicarbonate, acetate can be photo-assimilated, while propionate can be photo-assimilated by most strains; a few strains can utilize pyruvate, fructose, glutamate and protein. The bacteria cannot utilize thiosulfate, butyrate, higher fatty acids, ethanol and succinate, and cannot perform assimilation sulfate reduction.
The cells of Chlorobium vibrioforme are short arc-shaped, and the bacterial cells are 0.5-0.7 microns wide and 1-2 microns long. In natural habitats and under adverse culture conditions, helical types that are wound into tight coils appear. The color of single cells is light green and the color of cell suspensions is green. Chlorobium vibrioforme is an obligate photoautotroph and strictly anaerobic. Most strains require VB12 and at least 1% NaCl. Optimum growth pH range: 6.0-7.5. Optimum growth temperature: 25°-30°C. Electron donors for photosynthesis: sulfide, sulfur. In the presence of sulfide and bicarbonate, acetate is photoassimilated, while propionate is only photoassimilated by most strains. The bacteria cannot utilize thiosulfate, higher fatty acids, ethanol, and succinate, nor can it carry out assimilation-type sulfuric acid.
Figure 2. The Immunofluorescence of Chlorobium phaeobactercides.(A D Cahill, et al.;1995)
The cells of Chlorobium phaeobactercides are rod-shaped, occasionally slightly curved, 0.6-0.8 microns wide and 1.3-2.7 microns long. The color of the cell suspension was yellow to reddish brown to chocolate brown. Chlorobium phaeobactercides is obligately photoautotrophic and strictly anaerobic. Its growth process requires VB12. Strains in seawater require at least 1% NaCl. Optimum growth pH range: 6.0-7.5. Optimum growth temperature: 25°-30°C. Photosynthetic electron donors: sulfide, sulfur. Acetate or fructose can be photoassimilated in the presence of sulfide and bicarbonate. During the cultivation process, the bacteria cannot utilize thiosulfide salts, higher fatty acids, propionate, propionate, ethanol, sugar alcohols, hydrogen and methane, and cannot perform assimilation-type sulfuric acid reduction.
The cells of Chlorobiurn phaeovibrioides are slightly curved to arcuate, 0.3–0.4 μm wide and 0.7–1.4 μm long; in some cases, the cells are interconnected and grow into somewhat convoluted coils and spirals. Acetate and propionate can be photosynthesized in the presence of sulfide and bicarbonate. The rest of the characteristics are the same as Chorobium phaeobacteroides.
The culture of Chlorobium requires specific formulations of growth media for use in cloning, plasmid DNA preparation, and protein expression. Creative Biogene offers a selection of bacterial growth media and custom services for your specific application. If you are interested in our microbial anaerobic and aerobic culture platform, please contact us for more details.