On the decomposition of cellulose by an aerobic organism (Spirochaeta cytophaga, n. sp.).

Abstract

From the foregoing account the following summary may be given:1. Examination of Rothamsted soils on different occasions has revealed the presence of an organism capable of breaking down cellulose with comparative ease.2. This organism presents a number of features of morphological and physiological interest. Morphologically, the organism appears to possess greater affinities with the Spirochaetoideae than with the bacteria and the name Spirochaeta cytophaga is, therefore, suggested.3. While the spirochaet is capable of considerable vegetative growth as a sinuous filamentous cell, it also appears to pass through a number of phases which terminate in the production of a spherical body (sporoid) which differs in a number of respects from the true spores of the bacteria. Germination of the sporoid again gives rise to the filamentous form, which possesses perfect flexibility and is feebly motile. The latter does not apparently possess flagella.4. Spirochaeta cytophaga is essentially aerobic; its optimum temperature is in the region of 30°. Both the thread and sporoid stages are killed by exposure to a temperature of 60° for ten minutes.5. The nitrogen requirements of the organism may be met by a number of the simpler nitrogen compounds—ammonium salts, nitrates, amides and amino-acids. Peptone is also suitable in concentrations up to 0.025 per cent. Stronger solutions, e.g. 0.25 per cent., lead to marked inhibition of growth. The organism fails to grow on the conventional nutrient gelatine or agar.