Levan production by Bacillus polymyxa

Abstract

A levan-producing bacterium was isolated from soils and its characteristics for polysaccharide synthesis were studied. A series of enrichment and plating techniques enabled the isolation of a levan-producing bacterium from closely related contaminants. Cultural and physiological characteristics of the isolate identified the organism an a strain of Bacillus polymyxa. The organism produced about 40 g extracellular polysaccharide per liter of sucrose medium, which was about three times more yield than levan obtained from known levan producers. The highest amount of polysaccharide was on a 8% sucrose medium. Hydrolysis of the product showed that the polysaccharide consisted entirely of d-fructose, and13C.n.m.r. spectra confirmed that the product was levan, a fructose polymer linked by B-(2→6) fructofuranosyl linkage. © 1989 Society for Industrial Microbiology.