4 THE METABOLISM OF ALGAE 



In a third kind of investigation algal material has been 

 used in short-term biochemical experiments. Many algae 

 have qualities which particularly suit them for precise 

 physico-chemical investigation and have occasionally been 

 used as material by biochemists interested in particular 

 aspects of metabolism. Engelmann used algae extensively 

 in his elegant work, published in 1883,^^ on the light factor 

 in photosynthesis. Later, in 1919, Warburg^^o described 

 the use of Chlorella as a system in which photosynthesis 

 may be studied under the least complicated conditions and 

 since then this and similar species have played an increas- 

 ingly important part in the elucidation of the mechanism 

 of this process. The investigations of oxidative assimilation 

 by the colourless alga Prototheca, reported by Barker in 

 1935-6,22' 23 provide an example of work with algae which 

 is of fundamental importance in another field of bio- 

 chemistry. 



The distinction between these various lines of research, 

 clear-cut for many years, is now disappearing as it becomes 

 more generally recognized that the metabolism of the algae 

 is a distinct field of study in itself and that to be properly 

 understood its various aspects must be related one to 

 another. The comparatively late development of this atti- 

 tude is shown by the fact that no comprehensive reviews 

 of algal physiology or biochemistry appeared until those of 

 Myers and'^Blinks in 1951.200. ^^ Part of the present increase 

 in interest in the subject is a reflexion of the general develop- 

 ment in microbiological chemistry that has occurred in 

 recent years; part is due to the economic necessity of obtain- 

 ing information about organisms which appear to have 

 considerable potentialities as sources of materials and power. 

 Seaweeds have always been utilized by man to some extent 

 and are now finding increasing use as raw materials for the 

 production of a variety of substances valuable in industry.208 

 The capacity for synthesis of microscopic algae has not as 

 yet been put to any direct economic use although it appears 

 likely that eventually their value in this respect may be 

 greater than that of the seaweeds. The harvesting of natur- 

 ally occurring planktonic algae does not appear to be an 



