Modification of alternan by novel Penicillium spp.

Four strains identified as Penicillium spp. were isolated from soil samples based on their capacity to modify the unique polysaccharide, alternan. Spores from these isolates germinated in medium containing alternan and reduced the apparent molecular weight of alternan as determined by high-performance size exclusion chromatography and viscometry. However, the fungi exhibited limited growth on alternan and did not consume the substrate. The rheological properties of the modified alternan resembled those of commercial gum arabic. Thus, treatment of native alternan with spores from these Penicillium spp. strains constitutes a simple bioconversion method to quantitatively produce novel and potentially useful modified alternan.