This data set contains the underlying data and information presented in the paper, "The development of a silage based biorefinery to deliver the maximum nutritional benefit for human consumption from UK grasslands". Water-soluble protein and vitamins were extracted from silage using a twin-screw extruder at room temperature. The solids from the extruder, which contained further insoluble protein and the carbohydrates from the silage, were depolymerised and used to culture the oleaginous yeast Metschnikowia pulcherrima, producing further mycoprotein and lipid from the system.

Included in the dataset are:

- an analysis of the silage feedstock, specifically the quantities of dry matter/ash, carbon and nitrogen, key essential amino acids, and Vitamin B1, B2, B3 (nicotinamide and nicotinic acid) and B6 (pyridoxine, pyridoxal and pyridoxamine);

- a comparison of amino acid profiles in the silage (before and after extraction) and a comparison to other common protein sources;

- a comparison of the performance of the extruder at different power levels, liquid feeding quantities, temperatures, and screw speeds, with regard to nitrogen content, protein content and yield;

- the fatty acid profile of the M. pulcherrima yeast grown on the resulting hydrolysate produced from the residues of the process.