#chloroflexota

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Chloroflexota vs. Chlorobiota

Chloroflexota propaganda here

Chlorobiota propaganda here

Chloroflexota vs. Chlorobiota

Chloroflexota

Chlorobiota

Voting ended onMar 8, 2024

[bacteriashowdown]

Chloroflexota

Group: Terrabacteria

Gram-stain: Varied

Etymology: For Chloroflexus aurantiacus. From the Greek "chloros", meaning "yellowish green", and Latin "flexus", meaning "bending", for their green color.

About: Chloroflexota, known for containing the "green non-sulfur bacteria", is a highly diverse and ubiquitous phylum. They exhibit a variety of oxygen tolerances, and may be aerobic, anaerobic, or somewhere in between. Members of Chloroflexota can be thermophiles or mesophiles, living in a range of environments such as hot springs, sea-floor sediments, soil, and anaerobic sludge bioreactors. They are largely chemoheteroorganotrophic, with several members also capable of photoautotrophy. Despite their prevalence, Chloroflexota have limited cultivability, and are therefore still quite understudied. The species Thermoflexus hugenholtzii are especially picky, with the narrowest growth-temperature range (in culture) of any known prokaryote (67.5°- 75° C).

On the Gram stain, Chloroflexota show varied results. Most are monoderms, having only one cell membrane, but many still stain gram-negative. This is due to the unique composition of their cell walls (one factor of which is the higher presence of a molecule called "pseudopeptidoglycan", rather than being primarily peptidoglycan). There are also plenty of gram-positive, spore-producing Chloroflexota. These share similarities with Actinomycetota and fungi, since they produce spores using hyphae, and form mycelium.

The name "green non-sulfur bacteria" is associated with the family Chloroflexaceae, in the order Chloroflexales. The Chloroflexales are known as the "filamentous anoxygenic phototrophic bacteria", or FAPs, for their style of photosynthesis that does not produce oxygen (in contrast to Cyanobacteriota and plants). There are "red FAPs" and "green FAPs", with the green FAPs constituting the green non-sulfur bacteria, in the family Chloroflexaceae.

Green non-sulfur bacteria share many similarities with their counterparts, the green sulfur bacteria (Chlorobiota), despite being distantly related. Both groups form the same antennae structures, filled with bacteriochlorophyll-containing chlorosomes that color them green. Chloroflexaceae, however, are not primarily photosynthetic. Instead, they are facultative anaerobes who tend to use a chemoheterotrophic metabolism in the presence of oxygen, and a photoautotrophic metabolism in its absence.

Another interesting family of Chloroflexota are the Dehalococcoidaceae, because they are involved in halogen-cycling. The bacteria are organohalide-respiring (halogens are reactive elements belonging to the group containing fluorine and chlorine, and an organohalide is an organic compound with a carbon-halogen bond). Thanks to this style of respiration, Dehalococcoidaceae are able to thrive in chlorinated environments. This makes them useful in the bioremediation of chlorine-contaminated ecosystems. Also, they can produce metabolites that smell like garlic.