RECYCLE OF LEACHATE DURING LIGNOCELLULOSIC CONVERSION PROCESSES

摘要

The present invention provides a process for producing fermentable sugar or a fermentation product from a lignocellulosic feedstock. The process comprises leaching the lignocellulosic feedstock with an aqueous solution to remove at least potassium salts from the lignocellulosic feedstock and without significantly hydrolyzing hemicellulose and cellulose, thereby producing a leached feedstock and leachate. The leachate is removed from the leachate and concentrated. The leached feedstock is hydrolyzed to produce fermentable sugar, which may be fermented to produce a fermentation broth comprising the fermentation product. The concentrated leachate is recirculated to one or more stages in the process involving alkali addition to adjust the pH of a process stream.