| STRICT ANAEROBES | Clostridium spp. |
| Desulfovibro | |
| Desulfotomaculum | |
| Methanogens e.g.Methanococcus | |
| PHOTOTROPHIC ANAEROBES | Chromatium |
| Chlorobium | |
| Thiopedia | |
| Ectothiospira | |
| FACULTATIVE (aerobic when not fixing N) | Klebsiella |
| Bacillus | |
| Enterobacter | |
| Citrobacter | |
| Escherichia | |
| Proprionibacterium | |
| FACULTATIVE PHOTOTROPHS | Rhodospirillum |
| Rhodopseudomonas | |
| MICROAEROPHILES( normal aerobes when not fixing N) | Mycobacterium |
| Thiobacillus | |
| Spirillum | |
| Aquaspirillum | |
| Methanosinus | |
| Rhizobium | |
| MIRCOAEROPHILIC PHOTOTROPHS | Plectonema |
| Lyngbya | |
| Oscillatoria | |
| Spirulina | |
| AEROBES | Azotobacter |
| Azotococcus | |
| Azomonas | |
| Beijerinckia | |
| Derxia | |
| AEROBIC PHOTOTROPHS | Anabena |
| Nostoc | |
| Calothrix | |
| Gloeocapsa | |
| 7 other genera of blue-green algae |
