With the inevitable exhaustion of supplies of oil and other fossil fuels looming on the horizon, coupled with the increasing concern regarding the environmental impact of using these resources, governments worldwide are under pressure to invest in the development of renewable replacements for fuel, as well as natural alternatives to oil based materials such as plastics. One of the main sources of interest is lignocelluloses, comprised of three main components - lignin, cellulose and hemicellulose each of which can be a valuable raw material for fuel or polymer production. The problem however is that the three components are bound together chemically, and efficient separation requires a combination of physical and chemical treatments. It is the aim of this project, therefore, to develop novel processing for the hydrolysis of lignocellulose. The process will involve the use of Ionic Liquids, essentially salts which are liquid below 100°C. While these chemicals have been known of for decades, it is only in the last twenty years or so that research into their potential as solvents, catalysts, reaction media, etc. has accelerated and interest has increased in their use in biorefining. This project is concerned specifically with novel methods incorporating an acidic, hydrophobic ionic liquid in the hydrolysis of lignocellulose with the aim being to produce nanocellulosic fibres and examine their performance as composite fillers. This began with the analysis of novel ionic liquids based on phosphonium and choline cations in the hydrolysis of wheat straw. From this the most promising medium was evaluated in its ability to refine cellulose and compared with a traditional hydrolysis method using dilute sulphuric acid. Furthermore novel lignocellulosic feedstocks, anaerobic digestate and spent mushroom compost, were analysed to determine their suitability as sources for nanocellulosic fibres which would represent an innovative use of these waste materials.