Polysaccharides are sugar chains that provide a sustainable alternative to petroleum-based materials. The properties and applications of polysaccharides depend on the layout of sugar building blocks in the chain. To fully harness the potential of polysaccharides as biomaterials, we need to be able to control how they are made by living organisms. Polysaccharides are often assembled by enzymes that transfer a specific type of sugar to another one, creating a chain with defined sequence and properties. The project aims to control and engineer how these enzymes combine the sugar building blocks. This will help us understand how polysaccharides are assembled and at the same time allow us to make polysaccharides with new sequences. Using this knowledge, we hope to one day be able to design tailor-made polysaccharides and biomaterials with unique functions needed in a greener society.