Environmental Engineering Reference
In-Depth Information
Biocidal
Direct activity
Biofouling
adhesive
degrading
Enzymic anti-
fouling
Substrate from
seawater
Indirect activity
Coating of
surface with
substrate
Figure 2.18
Enzyme technology for anti-fouling
Other anti-fouling enzymes that have received attention are oxidoreductases,
including glucose oxidase and hexose oxidase, which produce hydrogen peroxide
(H
2
O
2
) that may induce oxidative damage in living cells. Kristensen and co-workers
[81] evaluated the anti-fouling potential of H
2
O
2
produced enzymically in a coating
containing starch, glucoamylase and hexose oxidase. After immersing it in sea for
97 days, the control surface with no enzymes had 35−40 barnacles, 10% of the area
was covered by diatoms and 15% of the area was covered by tunicates. The enzyme
coated surface had only 6−12 barnacles, 10% of the area was covered by diatoms
and no tunicates were present. The enzyme coated surface performed in a similar
way to a copper-based commercial coating.
It is known that QS plays an important role in the bioilm formation. AHL are required
for QS by some gram negative bacteria. AHL acylase can be used to degrade AHL.
Cao and co-workers showed that with increase in concentration of this enzyme, the
bioilm formation is inhibited [62].
2.5.3.2 Non-toxic Anti-fouling Coatings: Non-sticking Foul Release
Coating
The foul release coating (FRC) method involves an environment friendly approach.
The design of anti-fouling surfaces are based on minimising the forces of interactions
between the biomolecules and the synthetic surface so that adhered cells are easily
released or dislodged under low shear stresses [10]. A number of polymer surface
