H. Achenbach

The intensively yellow antibiotic xanthocillin is produced in cultures of Peni-cillium notatum Westling (Rothe, 1950, 1954). Its structure has been established as l,4-(4-hydroxyphenyl)-butadiene-(l,3)-diisonitrile-(2,3) (I) by chemical investigations of Hagedorn and Tonjes (1957). 

The natural occurrence of the isonitrile grouping in the structure of xanthocillin is unique and is of particular interest from a biogenetic point of view. 

For the fermentation of Penicillium notatum Westling a medium according to Czapek-Dox with some yeast extract added has been found suitable (Rothe, 1953) The cultivation is performed on rotatory shakers at 23—25 C. Synthesis of xanthocillin starts approximately 4 days after inocculation and increases as shown in Fig. 1. Obviously there is some relation between the observation of autolysis in the mycelium and the increase in the formation of xanthocillin. On approximately the 9 day the concentration of xanthocillin reaches its climax. Yields above 1 mg antibiotic per milliliter of fermentation broth are possible. 

The antibiotic is extracted with ether from the washed and dried mycelium and crystallizes from methanol in needles. The content of xanthocillin can be determined in alkaline solution by measuring the extinction at 413m[jL. 

Because of its symmetrical structure it is supposed that xanthocillin may originate by radical bonding of two biogenetically equivalent precursors. These precursors could be derived from the amino acid tyrosine. It is difficult to formulate a plausible biogenetic scheme for the formation of the isonitrile groups on the basis of any known biogenetic pathways. 

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HCA2579 W. Eberbach, M. Perroud-Argiielles, H. Achenbach, E. Druckrey and H. 

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