THE DECOMPOSITION OF CELLULOSE BY AEROBIC BACTERIA

Abstract

It is shown that a rapid and abundant growth of aerobic, cellulose-decomposing bacteria is obtained by use of this simple and specific medium: NaNO3, 0.50 gm.; K2HPO4, 1.0 gm.; MgSO4-7 H2O, 0.50 gm.; KC1, 0.50 gm.; FeSO4-7 H2O, 0.01 gm.; distilled H20,1000 gm. Five cc. portions of this medium are introduced into test tubes containing a strip of filter paper partly immersed. The slightly alkaline reaction (pH 7.5) favors bacterial but retards fungous growth. The low concentration of N salts shortens the incubation period, since, in almost all cases, cellulose decomposition can be recorded after 36-72 hrs. at 28[degree]C. Growth is obtained even when 1 or few cells are used for inoculation. Pure cultures of organisms belonging to 3 physiological groups have been isolated by this method: (a) Strict aerobes[long dash]unable to utilize any of the carbon compounds tested, except cellulose; (b) strict aerobes[long dash]cellulose decomposers growing well on starch agar but not on nutrient agar; (c) facultative anaerobes[long dash]cellulose decomposers, growing well in all ordinary media.