Abstract
Cobalamin (vitamin B12) belongs to group B vitamins soluble in water; it is an essential human nutrient - acts as a cofactor of two colalamin-dependent enzymes. A deficiency of cobalamin leads to anemia and neuropathy.
Its recommended daily requirement for adults is 2-4 μg. Biosynthesis of cobalamin is nowadays restricted to certain bacteria and archaea; industrially is produced by selected and genetically optimized microorganisms, mainly by Propionibacterium shermanii and Pseudomonas denitrificans strains.
Some plants and many animals including humans require cobalamin but do not synthetize it. Naturally rich source of cobalamin is food of animal origin: meat, fish, shellfish, milk and dairy products, eggs.
In plant foods, substantial amounts of active form of cobalamin were found in certain species of edible algae-Enteromorpha sp. and Porphyra sp. (known as nori), in some eukaryotic microalgae (Chlorella sp.), edible mushrooms (e.g. Shiitake) and tempeh-fermented soya product.
However, reliability of this plant sources remains uncertain.