A system for treating biomass for the production of a composition of lignin pellets .is disclosed. Pellets comprising at least 50 percent lignin by dry weight is disclosed. Also disclosed are pellets produced from a lignin composition by a process comprising: pre-treating lignocellulosic biomass into pre-treated biomass; separating the pre-treated biomass into a first liquid component comprising sugars and a first solids component comprising cellulose and the lignin composition; hydrolysing the first solids component of the pre-treated biomass into a hydrolysed biomass comprising sugars and the lignin composition; separating the hydrolysed biomass into a second liquid component comprising sugars and a second solids component comprising the lignin composition; supplying the second solids component comprising the lignin composition to a pelleting apparatus to produce the pellets; wherein the lignocellulosic biomass comprises cellulose, hemi-cellulose and lignin. According to an aspect, at least a portion of the lignin is not sulfonated.