Caulobacter crescentus holdfast: A bio-based and water-resistant adhesive
MetadataShow full item record
Due to climate change, society demands more environmentally friendly products. An excellent way to approach this is to develop more circular, waste-free, zero/negative emission or biodegradable products. For something to be biodegradable it has to be completely biobased. A few examples of biobased materials are hemp isolation panels and furniture created out of mycelium bio-composites. Something that does not have a biobased alternative yet is a good performing underwater glue. There is a lot to gain here because even synthetic glues lack strength under wet or underwater conditions. This hypothetical biobased glue could be incredibly useful in the industrial field but also in the medical field to quickly repair bleeding wounds. In order to create a new biobased and environmentally friendly product of high quality, it is often a great start to look at the solutions provided by nature. Organisms first developed in the sea and animals like sand-castle worms, mussels and barnacles have already found ways to make excellent underwater glue. They mainly use a glue that is made of proteins to adhere to any underwater surface. Scientists have tried to mimic these glues but due to their complexity they have not yet succeeded in making an equally strong and marketable biobased underwater glue. Another type of organisms that produce underwater glue are bacteria, especially the bacterium Caulobacter crescentus, which creates a holdfast that is currently the record holder of the strongest natural underwater glue ever measured. According to a few experiments it could hold a weight of 680 kg per cm2, the equivalent of holding a large horse with a glue surface area the size of a small coin. However, because the bacterium C. crescentus produces so little of the holdfast, it has been difficult to study and we currently do not know where its adhesive strength comes from. A few advancements have been made recently that might enable to investigate this holdfast further. Once the exact structure and chemical components of holdfast have been discovered we might be able to understand why it is so strong. This might help us with developing a new type of glue inspired by this holdfast. Other than its exact chemical composition we also want to know how the holdfast is produced by studying its biosynthetic pathway. This will not only give us more insights in how holdfast is created but might also allow us to mimic it ourselves. To produce the glue ourselves, it might be possible to genetically modify C. crescentus so that it produces a lot more of the holdfast. Alternatively, we could try to insert the biosynthetic pathway of holdfast in another more well-known and easy to culture bacterium like Escherichia coli. Then this bacterium will produce the holdfast for us in large quantities, something that is already done with certain medicine like hormones and vaccines. When we produce enough holdfast, we can do more mechanical testing and experiments on the properties of holdfast to find out if it would be suitable as a new underwater/wet adhesive.