Figure 5

Biofilm development during microbial limitation. Confocal scanning micrographs of Clostridium thermocellum biofilms on Whatman #3 filter paper chads taken midway during the ‘biofilm invasion’ region. Low magnification images (below) show varying degrees of biofilm colonization (green) on cellulose fibers (red); where it is common to observe surface fibers with little to no biofilm growth. High magnification imaging (above) of selected heavily populated fibers shows the typical cell monolayer biofilms of this species, with cells closely lining the substratum. Dividing cells (red circles) and occasional small spore-forming cells (green dots) are observed at the surface. Cells stained with SYTO 9 (green); cellulose fibers stained with WGA-TRITC (red).