The white button mushroom Agaricus bisporus is produced and consumed at large scale. It is low in fat and rich in protein and fibre. The white button mushroom is produced on compost of straw and horse manure. The process of composting and growth of the white button mushroom is a near black box. For instance, it is not known which sugar components are converted (and which are not) and when this takes place in the process. The aim of this project is to understand and improve the degradation of the sugars in the substrate during composting and growth of the white button mushroom.