New pigments derived from vitamin B12 by a strain of Aerobacter aerogenes present in river mud

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Abstract
Crude cultures from river mud containing predominantly Aerobacter aerogenes produces a brownish-yellow pigment (pigment I) and a yellow pigment (pigment II) when grown in the presence of vitamin B12 in a synthetic salt-glucose medium or a meat-extract medium. Pure cultures of both the rough and the smooth type of Aerobacter aerogenes were also shown to possess this property. Both pigments are derived from vitamin B12. Pigment I has been shown to contain cobalt. It is positively charged at pH 2.5 and negatively charged at 6.5. It has a distinct peak in the UV region at 262 mu and lacks the large peak in the 300-400 mu region characteristic of vitamin B12. In potassium cyanide the pigment turns pink and there is a bathochromic shift in the spectrum. This reaction is reversible. Pigment II is also positively charged at pH 2.5 and negatively charged at pH 6.5 and lacks the large peak in the 300-400 mu region. Within certain limits the formation of pigment I increases linearly with the concentration of vitamin B12. The formation of this substance is very slow and requires 12 days to obtain maximum yield. Anaerobic conditions greatly favour its formation, and the yield is also very dependent on the glucose concentration, reaching a maximum at a glucose concentration in the region 0.8-1.2%. No detectable formation of pigment I and II was achieved with the following bacteria Bacillus subtilis, B. cereus, Streptococcus faecalis, Sarcina lutea and Staphylococcus aureus H.

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