Chemosynthesis at denitrification with sulfur as 



source of energy. 



Proceedings of the Section of Sciences, Kon. Akademie van Wetenschappen, Amsterdam, 



Vol. XXIT, 1920, p. 899 908. Verscheen onder den titel Chemosynthese bij denitri- 



ficatie met zwavel als energiebron in Verslagen Kon. Akademie van Wetenschappen, 



Amsterdam, Wis-en Natuurk. Afd., Deel XXVIII, 1920, biz. 845-856. 



In photosynthesis organic matter results 'from the reduction of carbonic acid 

 by light as source of energy; the same tak"es place in chemosynthesis by 

 chemical energy. Organisms with photo- or chemosynthesis are called autotrophes; 

 those which feed on other organic substances are heterotrophes. The product of 

 chemosynthesis is the body substance of the producers, always spore-free bacteria. 



I described chemosynthesis at denitrification with sulfur as source of energy, 

 on 16. April 1903 at the 9 th Dutch Congress of Natural and Medical Science 1 ). 

 I then thought that in the process a facultatively anaerobic bacterium was 

 concerned difficult to isolate by the plate-culture method. It was further presumed, 

 that this species produced so much organic substance by chemosynthesis that 

 the many directly visible bacteria, denitrifying with organic food, might live 

 thereon. This supposition has proved to be erroneous ; the latter themselves are 

 in fact the operators of the sulfur denitrification as well as of the chemosynthesis. 

 They are easily cultivated on broth-agar or broth-gelatin, but then they lose, and 

 this is the new view, their autotrophy together with the power of sulfur deni- 

 trification, whilst preserving this power with organic food. The loss is caused by 

 the growth with organic food and this loss being hereditarily constant, we have 

 a case here similar to that which I described earlier for the nitrate ferment, and 

 which I called physiological species formation* 2 ). Just as I then distinguished 

 the oligotrophic from the polytrophic state we may in this case speak of the 

 autotrophlc and the heterotrophic condition of the operators 3 ). The heterotrophic 

 forms is thus some common denitrifying bacterium. 



On account of the little acquaintance with chemosynthesis acquired until 

 now, I will begin with describing once more the original experiment' 1 ). 



') Phenomenes de reduction produits par les microbes. Archives Neerland. Ser. 2. 

 T. 9, Pag. 153, 1904. 



2 ) These Proceedings. Vol.23, Pag 1163, March 28 (10 April) 1914. 



s ) As the existence of chemosynthesis is proved with certainty for the sulfur de- 

 nitrification, but not for the nitration, the same nomenclature could not be followed 

 in the two cases. 



4 ) An enumeration of the chief processes accompanied with chemosynthesis is to 

 be found in my paper: Bildung und Verbrauch von Stickstoffoxydul durch Bakterien. 

 Centralbl. f. Bakteriologie 2te Abt. Bd. 25, Pag. 30, 1910. 



