THE POLYSACCHARIDE PRODUCED BY AZOTOBACTER INDICUM

Abstract

A procedure was developed for the isolation and purification of the polysaccharide produced by Azotobacter indicum which resulted in a product containing approximately 5% ash, 0.4–0.6% nitrogen, and 40% carbon. Qualitative tests showed the absence of galactose, pentoses, ketoses, and amino and methylated sugars, and the presence of glucose and a uronic acid. A technique for determining combined uronic acids resulted in a value of 30% uronic acid on the untreated (unhydrolyzed) polysaccharide, and the remaining components were determined by analysis of the material after acid hydrolysis. The relatively severe conditions required to hydrolyze the polysaccharide indicate that the components are present in the pyranose form. The results obtained when the hydrolyzates were analyzed by paper chromatography, the spectrophotometric reactions of Dische, and other specific quantitative assays showed that the polysaccharide is a polymer of glucose, glucuronic acid, and an aldoheptose in the ratio of 3: 2: 1. Infrared analysis confirmed the presence and relative proportion of the uronic acid residues and indicated that the sugar units of the polysaccharide are probably in the beta configuration.