用細菌發酵(Pseudomonas denitrificans and Propionibacterium shermanii)合成的B12,Pseuomonas有Cell Wall, 算是植物
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http://en.wikipedia.org/wiki/Vitamin_B12...
Synthesis
Vitamin B-12 cannot be made by plants or animals[5] as only bacteria have the enzymes required for its synthesis. The total synthesis of B-12 was reported by Robert Burns Woodward[6] and Albert Eschenmoser,[7][8] and remains one of the classic feats of organic synthesis.
Species from the following genera are known to synthesize B-12: Aerobacter, Agrobacterium, Alcaligenes, Azotobacter, Bacillus, Clostridium, Corynebacterium, Flavobacterium, Micromonospora, Mycobacterium, Nocardia, Propionibacterium, Protaminobacter, Proteus, Pseudomonas, Rhizobium, Salmonella, Serratia, Streptomyces, Streptococcus and Xanthomonas.
Industrial production of B-12 is through fermentation of selected microorganisms.[9] The species most often used,
Pseudomonas denitrificans and Propionibacterium shermanii, are frequently genetically engineered and grown under special conditions to enhance yield.