Mechanism of Microbiological Decomposition of Cellulose

Abstract

Knowledge of the mechanism of microbial action on cellulose is important for the solution of problems not only in textile technology but also in agronomy, plant pathology, bacteriology, mycology, medicine, geology, and the wood, paper, photographic, and allied industries. Our present picture concerning the mode of breakdown of the cotton fiber is as follows: Upon germination, the microorganism secretes enzymes which first digest the cuticle. The hyphae of fungi then penetrate the secondary cellulosic wall directly into the lumen, where profuse growth ensues. Bacteria, on the other hand, adhere to the outer surface and pit their way inward. In both cases, digestion of cellulose occurs at the point of immediate contact with the organism. In submicroscopic regions of the fiber, the amorphous cellulose is more rapidly attacked than the crystalline. The native cellulose molecule is first converted by an enzyme (called cellulase by the author) into a linear polysaccharide. Another enzyme then hydrolyzes the linear chain directly into glucose, without the intermediary of cellobiose. The proposed mechanism differs significantly from that of Pringsheim and of Winogradsky. Based on this picture, topochemical modification appears to be very promising as a means of imparting simultaneously two or more properties to cotton fabrics, one of which is mildew proofness.