Utilisation of bacteria Utilisation of bacteria for anti-fouling biofilm for anti-fouling biofilm

able to avoid the able to avoid the settlement and growth settlement and growth

of micro&macro of micro&macro organismsorganisms

Fouling mechanism

• 1: adherence of bact. Colony (Van der Waals)

• 2: anchoring (pilis)

• 3: polysaccharide matrix

• 4: M.O. Attachment

• 5: More fouling

State of research...

• Study of inhibitory effect of various bact. strains on various M.O.

• Characterization of attachment mechanism of fouling agents

• Characterization of inhibiting extracellular products

Advantages/drawbacks

+ -

Up to 90 % inhibition of MO

Many different MO types → effect limited to spec. species

No toxic paint on hulls Mutations: cancel inhib. effect

Feasibility• Genetically: ?• Sea: very complex medium• Need significant upstream research

(surface materials, ) • Need experimental validation of designed

bacteria with many different conditions → more time than actual engineering ?

• Lots of economical interest in this

Bacteria used

• Alteromonas

• Pseudoalteromonas : extensively studied for its anti-fouling activity

=> Inhibit the settlement and growth of a large number of organisms

Anti-fouling substance produced

• Protein or peptide• Thermostable• Hydrophilic• >3500 daltons in molecular size

Inhibition of settlement by 2 ways:- direct: induce lysis in cultures- Indirect: emission from the bacteria of chemical

products which inhibit growth and settlement

Two possibilities

1. Continuous secretion of a given molecule which will avoid the deposit of molluscs on the hull

1. Secretion in response to a given input (e.g. shear stress)

Description of the bioparts

1. Input: when bacteria sense an external input, triggering of the production of a certain molecule to avoid the deposit of plants and mollusc, for example in response to pressure => possibility to use luxR for example for the modelisation = inducible promoter, normally off, which turn on in response to an external input

Description of the bioparts

2. Output: the bacteria can produce a molecule in order to kill molluscs attached or to prevent the adhesion.

=> possibility to use something like GFP as an output in our modelisation

Description of the bioparts

• 3. Filter: need to avoid the noise

coherent feedforward loop with AND-gate.

Input fast degrading primary messenger stable secondary messenger AND-gate