Table 1.

Main morpho-physiological characteristics of the strains used in this study.

Name	Morpho-physiology	Reference
Chromatium okenii strain LaCa	Purple sulfur bacterium; rod-shaped cells, 8.0–10.0 μm in size, Gram-negative; motile through flagella; sulfur assimilated in intracellular sulfur globules; anaerobic or microaerophilic growth; CO2 fixation by the Calvin-Benson-Bassham (CBB) cycle	Luedin et al. (2019a)
Thiodictyon syntrophicum strain Cad16T	Purple sulfur bacterium; round-shaped cells, 1.4–2.4 μm in size, Gram-negative; non-motile, vacuolated; sulfur assimilated in intracellular sulfur globules; anaerobic or microaerophilic growth; CO2 fixation by the Calvin-Benson-Bassham (CBB) cycle	Peduzzi et al. (2012)
Chlorobium phaeobacteroides strain 1VII D7	Green sulfur bacterium; rod-shaped cells, 0.6–1.3 μm in size, Gram-negative; non-motile; sulfur deposited in extracellular sulfur globules; strictly anaerobic growth; CO2 fixation by the reverse tricarboxylic acid (rTCA) cycle	Overmann (2006)