Pfizer Handbook of Microbial Metabolites 



94 



Oxygen-containing carotenoids appear at an early stage in the 

 biosynthetic scheme. Based on the order of appearance in cul- 

 tures of Neurospora crassa, Grob has proposed* the following 

 partial pathway of carotenoid formation: 



7-Carotene 



Lycopersene has not been isolated from a natural source, but 

 this colorless polyene has been synthesized and seems to be a 

 logical early member of this sequence. 



* See addendum. 



