Slimes (Biofilms)
Microbial slimes are now more commonly called biofilms. They similar in composition to capsular material.
Sometimes there is particulate matter in the slime, and there may be a
sheath, encrustation, or imbedded mineral matter formed by the
microorganisms. Slimes are inhabited by the organisms that create
them as well as other organisms seeking protection or food. Protozoa
can move through a fluid slime in search of prey as the slime closes
in their wake. There is a random distribution of organisms
in the slime unless there is an advantage to a particular location. For example,
motile organisms (those with flagella) may migrate to the regions where oxygen
concentration is highest.
Archive of great biofilm material.
Flocculation of microorganisms is of practical importance because flocculated
organisms are relatively easy to collect for recycle, to retain in the
bioreactor, or to harvest. Slimes and flocs are continuous.
Pellets, on the other hand, may be networks of filaments resembling a tangle
of fishing line but on a tiny scale. Fluid can pass through the pellet, but
at a slow rate because the small size of the open spaces presents high
resistance. Hydraulic deformation of a filamentous floc may squeeze out
interstitial water and thus aid mass transfer. By contrast, the viscosity of
slime retards convection and slows molecular diffusion.
click here to go to main menu
Go
"with the flow to next section"
"DONE"