Carotenes and Carotenoids 



Carotene pigments are widely distributed throughout nature, 

 and many microorganism pigments are carotenoid. Their iso- 

 lation and characterization are often comphcated by the co-oc- 

 currence of closely related compounds, and in some cases by 

 poor stability. Many identifications have been made on the 

 basis of ultraviolet absorption spectra alone. 



For these reasons, and because of dupHcations in nomencla- 

 ture, the literature dealing with microorganism carotenoids is 

 confused. The situation has been reviewed by T. W. Goodwin,^ 

 and to augment the entries in this section some pertinent tables 

 and references from this book have been incorporated as an 

 appendix. 



Carotenoids occur in both photosynthetic and non-photosyn- 

 thetic microorganisms, and their functions are not established 

 clearly. In fungi they may stimulate photokinetic responses 

 such as phototropic bending. In sarcina and staphylococcus 

 species there may be some protection of the cell from ultraviolet 

 light. In photosynthetic genera it has been suggested that 

 carotenoids may -serve as blue-light energy absorbers, as oxygen 

 carriers and in the prevention of chlorophyll-catalyzed photo- 

 oxidations. 



The work that has been done on carotene biogenesis in micro- 

 organisms has been well summarized.- ^ It has been found* ^ 



^ T. W. Goodwin, "Comparative Biochemistry of Carotenoids," 

 Chemical Publishing Co., Inc., New York, N. Y., 1954. 



- G. E. W. Wolstenholme and Maeve O'Connor, "CIBA Foundation 

 Symposium on the Biosynthesis of Terpenes and Sterols," E. C. Grob, 

 The biosynthesis of carotenoids by microorganisms, Little, Brown 

 and Co., Boston, Mass., 1959, pp. 267-278. 



3 T. W. Goodwin, ibid., pp. 279-294. 



