Facultative-Chemolithotrophs,Heterotrophically,Chemolithotrophs,Photosynthetic,Autotrophs,Organic Acids

Facultative Chemolithotrophs

	Facultative Chemolithotrophs -Chemolithotrophs which can grow autotrophically (i.e; in a mineral salts medium with CO2 as the source of carbon and inorganic compounds for energy) or heterotrophically (using organic compounds for both carbon and energy) are termed facultative chemolithotrophs (Matin 1978).
Growth of facultative chemolithotrophs can be supported by a variety of organic compounds. In Thiobacillus A2 the sources of carbon and the energy source for growth are different hexoses, pentoses, organic acids, ά-linked disaccharudes and aromatic compounds. For T. nocellus, glutamate is a good - growth substrate. Glucose, acetate, succinate and malate have also been reported t9 support growth, but the evidence is not conclusive.
The key enzymes of the HMP, ED and EMP pathways have been found in cell free extracts of facultative chemolithotrophs. Several of the cytochromes and flavoproteins, ubiquinone and menaquinone have been reported.Chemolithotrophs can obtain all the energy required for growth from the oxidation of inorganic substances like ammonia, nitrite, hydrogen, sulphur compounds or iron.
They utilize CO2 as the source of carbon. Nearly all chemolithotrophs are also autotrophs. They are the non-photosynthetic primary producers of fixed carbon in the biosphere.

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Phototrophs Chlorobiaceae - Chlorobacteriacae Green S Bacteria Chloroflexaceae - Green Filamentous Bacteria Chromatiaceae - Thiohodaceae - Purple S Bacteria Rhodospirillaceae - Athiorhodaccae - Purple non-S Bacteria Cyanobacteria - Bule Green Algae - Blue Green Bacteria Prochlorophyta Chemotrophs Obligate Chemolithotrophs Facultative Chemolithotrophs Methanogenesis