T- 1. Essential nutrients and their industrial production methods; ( ) = demonstration, not yet commercial scale
Vitamin A (retinol/
+ Most industrially produced vitamin A is produced through chemical synthesis. Carotenoids like
b-carotene can also act as pro-vitamins; their breakdown in the body is converted into vitamin A.
Vitamin B1 (thamine) + Vitamin B1 is a cofactor for central metabolism enzymes. Deficiency leads to life threatening
neuropathic conditions. Produced through chemical synthesis.
Vitamin B2 (riboflavin) + + + Produced industrially through fermentation of the fungus, Ashbya gossypii, a natural
overproducer or of the bacteria, Bacillus subtilis, which has been genetically engineered to
overproduce riboflavin [ 8].
Vitamin B3 (niacin) + + Vitamin B3, an essential precursor to the NAD cofactor) is largely produced through enzymatic
or whole cell biocatalysis, although full chemical and fermentation based routes have been
demonstrated [ 9].
+ + (+) Pantothenic acid is required for synthesis of Coenzyme A. Chemical synthesis is most
common in industry, but fermentative bioconversion pathways have been demonstrated and
recombinantly engineered for increased production [ 10].
Vitamin B6 (pyridoxine) + A coenzyme involved in enzymatic reactions for amino acid, glucose and lipid metabolism.
Produced through chemical synthesis.
Vitamin B7 (biotin) + + + Biotin can be produced via chemical synthesis, fermentation from glucose with genetically
engineered Serratia marcescens, or through bioconversion using enzymes from Bacillus
sphaericus [ 11].
Vitamin B9 (folate/folic
+ Folic acid is an essential cofactor in many biosynthetic and cellular processes. It is produced
through chemical synthesis.
+ + Cobalamin is important for the nervous system function and the synthesis of red blood cells.
Produced exclusively through industrial fermentation with bacteria such as Propionibacteria
freudenreichii and Pseudomonas denitrificans. Genetic engineering in these organisms has
been used to increase titers [ 4].
Vitamin C (ascorbic
+ + + Industrially produced ascorbic acid (named for its anti-scurvy activity) through a two-step
fermentation of D-sorbitol to L-sorbose through Gluconobacter oxydans, then to 2-keto-L-
gulonic acid by Ketogulonicigenium vulgare, which is then lactonized to ascorbic acid [ 12].
+ + + Vitamin D3 (cholecalciferol) is produced through UV irradiation of 7-dehydrocholesterol
extracted from lanolin; D2 (ergocalciferol) is produced in a similar manner, starting with
ergosterol extracted from fungi [ 13].
Vitamin E (tocopherol/
+ + + (+) Tocopherols and tocotrienols are significant antioxidants. They can be produced chemically,
+ + Vitamin K compounds are quinones required for proper blood clotting. They are primarily
produced through chemical synthesis, but fermentative routes were demonstrated in Bacillus
subtilis [ 11].
Vitamin Q (ubiquinone,
+ + + Naturally produced by a diverse range of microorganisms, strains of E. coli were developed for
commercial scale production of CoQ10 through genetic engineering [ 15].
Essential fatty acids
+ + + Important dietary fatty acids are typically extracted from fish oils or produced through
bioconversion, extraction from fermenting microalgae or fungi, or in genetically engineered
yeast [ 16].
Carotenoids + + + (+) Important pigments, antioxidants and provitamins, the carotenoid family is largely produced
industrially through chemical synthesis. Carotenoids are also extracted from fungi (Blakeslea
trispora, Xanthophyllomyces dendrorhous) or algae (Dunaliella salina, Haematococcus pluvialis).
Biotechnological production in yeast was alsodemonstrated [ 17].
Amino acids + + + + A number of amino acids (lysine, threonine, tryptophan) are produced through fermentation
in wild and genetically engineered microorganisms (Corynebacgterium glutamicum, E.
coli) at high volumes for use primarily in animal feed. Other essential amino acids, such as
methionine, are produced through chemical synthesis [ 18].