A natural terrestrial biofilm

Abstract

Material recovered from an extensive and viscous biofilm found on areas of rough hill pasture in Southern Scotland proved to consist of a thick mucilaginous deposit of polysaccharide in which species of green algae, with Gleocystis spp as the dominant microorganism and lesser numbers of Oocystis spp. Cyanobacteria were also entrapped. On laboratory culture other green algal and cyanobacterial species were detected. Analysis of the native polysaccharide and of the exopolysaccharide from a mixed culture of the dominant algal species derived from the original material, revealed the major components as glucose, galactose, mannose and rhamnose. The content of uronic acids was very low. The viscosity of the polysaccharide preparations was determined and compared with bacterial biofilm material; viscosity was lost following phenol extraction indicating that the original material was probably closely associated with proteins. © 1996 Society for Industrial Microbiology.