Table 1.

Characteristics of phototrophic Gemmatimonadetes and six other bacterial phyla containing chlorophototrophic members

Phylum	Common name*	Reaction center	Main pigments	Carbon fixation pathway†	Oxygen requirement	Discovery
Cyanobacteria		Type 1	Chlorophylls, carotenoids, phycobilins	Reductive pentose phosphate (Calvin– Benson–Bassham) cycle	Aerobic	19th century
		Type 2
Proteobacteria	Purple bacteria	Type 2	BChl a/b, carotenoids	Reductive pentose phosphate (Calvin– Benson–Bassham) cycle	Aerobic, semiaerobic, anaerobic	19th century
Chlorobi	Green sulfur bacteria	Type 1	BChl a/c/d/e, carotenoids	Reductive tricarboxylic acid (Arnon–Buchanan) cycle	Anaerobic	Early 20th century
Chloroflexi	Green nonsulfur bacteria	Type 2	BChl a/c, carotenoids	3-Hydroxypropionate (Fuchs–Holo) bi-cycle	Semiaerobic	1974 (10)
Firmicutes	Heliobacteria	Type 1	BChl g, carotenoids	Absent	Anaerobic	1983 (11)
Acidobacteria		Type 1	BChl a/c, carotenoids	Absent	Aerobic, semiaerobic	2007 (12)
Gemmatimonadetes		Type 2	BChl a, carotenoids	Absent	Semiaerobic	This study

^*Common or historical name used for phototrophic species in the particular phylum.

^†If present.