A simple and precise assay for microbial and enzymatic decomposition of cellulose applicable in agricultural research

Abstract

AbstractThe process of microbial decomposition of cellulose is important in many agricultural situations. Study of the nature of the process, however, has been slowed by the inadequacy of methods of measurement. A highly sensitive alkali-swelling technique originally devised for detection and measurement of damage in raw cotton fibers in the field before harvest was later found to be useful also for basic studies of the process of cellulose decomposition by microorganisms and their cellulose enzymes. A weighed sample of cotton fiber is swollen in an 18% solution of sodium hydroxide, centrifugea free of interfibrillar solution, and then reweighed to determine the amount of alkali absorbed. The percentage weight increase is termed the fiber's “alkali-centrifuge value” or “AC value”. This test is applied before and after exposure of a test sample of fiber to growing microorganisms or to solutions of their cellulose enzymes. The cellulose enzyme complex measured in this fashion has been termed “the swelling factor” or “S factor”. Data reported here illustrate the use of the test in measuring effects on cotton fiber of microorganisms and associated S factor. The basic swelling measurement is simple to perform, involves only standard laboratory equipment, is adaptable to a wide range of fiber sample sizes, is inexpensive, and is capable of yielding highly reproducible results. The method can be easily and beneficially applied by scientists in both developed countries and in developing countries, since expensive and sophisticated laboratory equipment is not required.