Patent ID: 8123864

Claim:
A method of continuous hydrothermal pretreatment of lignocellulosic biomass feedstock having an amount of lignin comprising: (i). soaking of the lignocellulosic biomass feedstock having said amount of lignin in acetic acid containing liquid from a subsequent step of the hydrothermal pretreatment, followed by (ii) continuous hydrothermal pretreatment within a pressurized pretreatment reactor at temperatures between 170 and 200° C., wherein the feedstock is cereal straw, corn stover or bagasse, wherein, following soaking and pretreatment, the pretreated feedstock is subsequently subject to at least one pressing operation while it is still under pressure or after it has been unloaded from the pretreatment reactor to create a fibre fraction and a liquid fraction, wherein temperature and residence time for hydrothermal pretreatment within the pretreatment reactor are selected at lower severity than that required for pretreatments that seek maximal removal of hemicellulose from the fibre fraction such that greater than 80% of said lignin amount remains in the fibre fraction following the at least one pressing operation, further characterized in that the fibre fraction having greater than 80% of said lignin amount obtained following the at least one pressing operation is subsequently subject to enzymatic saccharification.