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A hydrophobic biofilm coating could be applied in wide range of fields, such as antifouling and protection of sensory or medical equipment. Hydrophobicity can prevent micro-organisms and spores from adhering to a surface, thereby preventing fouling and corrosion to occur. This effect can be used in antifouling coatings for ships, but also in biomedical technology to prevent bacteria from forming pathogenic bioflms on prostheses and catheters.


In nature, bacteria occur predominantly in highly organized multicellular communities called biofilms. Biofilm formation induces a complex developmental process, where cells differ from each other spatially and morphologically. The bacterial cells in such biofilms are composed of phenotypically different bacteria, demonstrating an intriguing example of heterogeneous regulation within an isogenic culture. Gram-positive bacteria have developed different strategies for survival in unfavorable environments, e.g. by getting competent or by sporulating. Biofilms offer an opportunity for the cells to survive extreme conditions as the cells in biofilms are more resistant to antibiotics and harsh circumstances. Micro-organisms form these complex structures to be better protected against physical stress, drought and competing organisms. Bacillus even forms highly complex biofilms with a large degree of structural complexity and diversivication of cell function within the biofilm. There are even channels withinn the biofilm to allow afvoer of bacterial wastes and diffusion of oxigen deep within the biofilm. Structure.jpg

Biofilm formation

Biofilm formation ussually starts with the accuulation of biomass, next the is the adhesion to a surface by the production of (adhesion proteins). Since the pathways involved in biofilm formation in Bacillus are just starting to be unravelled we not everything is known about the complex physiological interactions within a biofilm By using an already in Bacillus existing pathway for auto inducting of our hydrophobic proteins, we try to minimize the amount of tinkering to the existing signalling pathways. Thereby leaving File:Biofilm formation

Expression in a biofilm

To successfully auto induce expression of the chaplins in our biofilm, we have been studying relevant signalling pathways in Bacillus subtilis. Timing is one the most important factors in successful expression. Bacillus produces amyloidfibers called TasA .TasA is a very important protein in biofilm formation in Bacillus subtilis. TasA proteins form amyloid fibers thereby providing the biofilm with an increased degree of rigidity. Since chaplins also assemble into amyloid fibers, expressing chaplins at the same moment as TasA is expressed would maximize the chance of successful expression of chaplins while enabeling maximum biofilm coverage. Expression of tasA is initiated via quorum sensing, key signalling molecules in this pathway are the comx, surfA and yqxM initiating TasA expression.

Coating surfaces

Applying our bacteria effectively to a surface poses big challenges, such as, how to coat a surface in a short period with low cost and low tech methods. There must be enough nutrients for the organisms to successfully make a biofilm yet you want avoid smuddering you surface in medium or sustaining you culture for long periods to attain a biofilm.


Making a viscous medium paste could either be spayed or smeared on a surface, by adding corn starch to regular TY medium we increased the viscousity of our medium and also making more rich in nutrients. The result was a By experimenting with dioffenrent ration of corn strarch and agar.

File:Biofilm on ceramics

Biofilm paste

Making a viscous medium paste could either be spayed or smeared on a surface, by adding corn starch to regular medium, we have created an easyly applicable paste, so to grow our biofilmcoating on all kinds of different surfaces. Another effect of the addition of cornstarch to the medium is an increased growing speed. File:Ceramics A rok biofilm showing a high degree of structural complexity

Bacillus subtilis a an ideal candidate for a biofilm coating since it is fast growing and has a very rigid extracellular matrix.

TasA is a structural protein needed to form a biofilm in Bacillus Subtilis. A TasA deletion mutant does therefore not form a biofilm.

Normal Bacillus Subtilin biofilm on liquid air interface.

Biofilm Bacillus 1.jpg

Bacillus Subtilis TasA deletion strain, not forming a Biofilm

Biofilm Bacillus DeltaTasA.jpg