Cellulose Digestion by Organisms from the Termite Gut

Abstract

The termite thrives in an environment which is most unusual and which requires specialized adaptation for survival. Its galleries are largely cellulose as also is its diet. Relatively little combined nitrogen is found in its food other than that derived from consumption of fecal materials of its fellows. That sector of the nitrogen cycle which includes the metabolism of the termite is as yet unexplored.

It is probable that the energy requirements of the termite are derived from the destruction of cellulose. In addition to the energy required by the animal for its ordinary life processes an additional large amount must be available should it develop that there is any fixation of nitrogen connected with its metabolism. The question of cellulose splitting within the gut of the termite thus is of fundamental importance.

Cellulose digestion is not unknown among the invertebrates. Miller and Boynton 1 have demonstrated the appearance of glucose within the gut of Bankia, the Northwest shipworm. Werner 2 has shown that the digestion of cellulose within the intestine of Potosia cuprea, the rose chafer, is bacterial in character. Cleveland, 3 however, believes that the enormous numbers of bacteria found within the gut of the termite have no function as cellulose splitters within the intestinal canal of Reticulotermes flavipes, and his series is reported to have included at least 100 individuals.

Inasmuch as opportunity presented itself, through the courtesy of Dr. S. F. Light, to obtain termites from a variety of sources and of a number of different genera, we decided to make a further attempt to demonstrate the splitting of cellulose by bacteria derived from termite gut content. The technique was that usually followed in soil bacteriology. Flasks were prepared containing medium of the following formula: K₂HPO₄-1 gm.; MgSO₄—1 gm.; Na₂CO₃ —1 gm.; (NH₄)₂SO₄-2 gm.: CaCO₂—2 gm.; tap water 1000cc. A 2-inch circle of filter paper was added to each flask and the material then was autoclaved.