A process for concurrent production of lignins, fuel
alcohol, and
biogas from lignocellulosic feedstocks. The process comprises: (1) pretreating a lignocellulosic feedstock to produce a solubilised liquid components
stream comprising lignins,
lignin-derived compounds, and a cellulosic pulp
stream, (2) separating the liquid
stream from the cellulosic pulp stream, (3)
processing the liquid stream to separate and recover at least lignins,
lignin-derived compounds, and semi-
solid waste material, (b)
processing the cellulosic pulp stream to saccharify and ferment the
cellulose pulp to produce a beer which is then separated into fuel-grade
alcohol and a waste
stillage material, (4) anaerobically digesting the semi-
solid waste material from the liquid stream and the waste
stillage material to produce a
biogas. The rate of
anaerobic digestion can be manipulated by controllably supplying a portion of the monosaccharides produced from the cellulosic pulp. The cellulosic pulp stream may also be anaerobically digested.