For chemical composition determination, garlic straw (GS) residues were ground and 40–60 mesh fractions were selected. The procedures were performed according to standard T264 cm-07. The chemical composition of GS was determined according the following methods: holocellulose, cellulose and hemicellulose (TAPPI T257 om-09), lignin (TAPPI T222 om-11), ash (TAPPI T211 om-12) and extractives (TAPPI T207 cm-08). This allowed determining the weight fraction of cellulose, hemicelluloses, lignin, extracts and ashes contained in the GS sample. As recommended by the various standards used, all the experiments were performed by duplicate and results were presented as averaged between the two values with an experimental error below 5%.