Chapter 6 Characterizing and Understanding Biofilms
Section 3 Macro and Microscale Views of Biofilms
Page 3 Biofilm Reactors

Biofilm Reactors

Any well-equipped biofilm research laboratory will have a variety of reactors for growing biofilms under different environmental conditions.

Flat plate reactors

Flat plate flow cells are used to grow biofilms which can readily be analyzed microscopically. Most fundamental biofilm research is done at the microscale.

Flat Plate Flow Cell
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Staff, Center for Biofilm Engineering, Montana State University, Bozeman

Figure 1 . Flat Plate Flow Cell.
A flat plate flow cell is composed of two glass plates with a small gap in between. Fluid, cells, substrate and nutrients enter and exit through flow ports and biofilm is grown on the glass surface so as to be readily observable microscopically. The flow cell is well suited to analysis of biofilms at the microscale. A BioSurface Technologies FC81 Flow Cell is show.

Flow Cell Microscope Image Analysis
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Staff, Center for Biofilm Engineering, Montana State University, Bozeman

Figure 2. Flow Cell Microscope Image Analysis.
Here is the flow cell being used in conjunction with a scanning confocal microscope. The digital images from the biofilm growing in the flow cell are captured by the confocal and then analyzed using a variety of software-based techniques.
Streptocassus mutans
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Figure 3. Streptocassus mutans
This figure shows the type of images which come from flow cells.

Rotating annular reactors

Rotating annular reactors offer the capability of facilitating biofilm growth under pipe flow conditions.

Rotating Annular Reactor
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Figure 4. Rotating Annular Reactor
Biofilm growth at the meso scale (for pipe flow) can be studied using the rotating annular reactor shown here. This reactor consists of an annulus through which fluids are pumped at a set dilution rate. A rotating drum containing biofilm sample coupons on the outside is inserted inside the annulus. The drum rotational speed  can be varied thereby varying the shear stress exerted on the biofilm coupons. This system can simulate flow conditions which occur in pipes of various diameters and flow velocities.

Annular Reactor Coupon
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A. Cunningham, Center for Biofilm Engineering, Montana State University, Bozeman

Figure 5. Annular Reactor Coupon
Here is a sample coupon removed from an annular reactor operated using water from a drinking water treatment plant.

Drip Flow Reactors

Drip flow reactors simulate biofilms growing on surfaces without continuous flow.

Porous Media