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Method for the production of alcohol from a pretreated lignocellulosic feedstock

  • US 8,980,599 B2
  • Filed: 07/29/2008
  • Issued: 03/17/2015
  • Est. Priority Date: 08/02/2007
  • Status: Active Grant
First Claim
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1. A process for increasing the hydrolysis of cellulose in the production of alcohol from a lignocellulosic feedstock, comprising the steps of:

  • (i) pretreating a lignocellulosic feedstock under conditions to produce a composition comprising a pretreated lignocellulosic feedstock having a disrupted fiber structure and increased accessibility of the feedstock to being hydrolyzed;

    (ii) enzymatically hydrolyzing the pretreated lignocellulosic feedstock with cellulase enzymes to produce a hydrolyzate slurry comprising glucose and unhydrolyzed cellulose;

    (iii) fermenting said hydrolyzate slurry to produce a fermentation broth comprising alcohol and unhydrolyzed cellulose;

    (iv) separating the alcohol from the fermentation broth by distillation to obtain a stream comprising concentrated alcohol and a still bottoms stream comprising the unhydrolyzed cellulose and the cellulase enzymes, said distillation resulting in heat treatment of the unhydrolyzed cellulose, which heat treatment is conducted at a temperature between 70 and 200°

    C. so as to denature the cellulase enzymes; and

    (v) further hydrolyzing at least a portion of the still bottoms stream with cellulase enzymes to convert at least a portion of the unhydrolyzed cellulose present in said still bottoms stream to glucose, thereby increasing cellulose hydrolysis.

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