Metabolic Classification of MicroOrganisms
Carbon Source Energy Source Electron Donor
Inorganic Organic Light Chemical Inorganic Organic
Autotroph Phototroph Lithotroph
Heterotroph Chemotroph Organotroph
(eg. 2O2- ® O2 + 4e-)
A few important examples
Phytoplankton
Nitrifier bacteria Fungi
CO2, H2O CO2, NH4+ Protozoa
Most bacteria
Green & purple Colourless {CH2O}, {CH2O}
sulphur bacteria sulphur bacteria
CO2, H2S CO2, H2S
Chiefly CO2 as Chiefly O2 as Any oxidant
oxidant ® {CH2O} oxidant (eg.
O2 + 4e- ® 2O2-)