Bioethanol production from non-starch carbohydrate residues in process streams from a dry-mill ethanol plant.

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Abstract

Slurries obtained from process streams in a starch-to-ethanol plant, Agroetanol AB in Norrköping, Sweden, were used to assess the potential increase in bioethanol yield if heat treatment followed by enzymatic hydrolysis were applied to the residual starch-free cellulose and hemicellulose fractions. The effects of different pretreatment conditions on flour (the raw material), the stream after saccharification of starch, before fermentation, and after fermentation were studied. The conditions resulting in the highest concentration of glucose and xylose in all streams were heat treatment at 130 degrees C for 40min with 1% H(2)SO(4). Mass-balance calculations over the fermentation showed that approximately 64%, 54%, 75% and 67% of the glucan, xylan, galactan and arabinan, respectively, in the flour remained water insoluble in the process stream after fermentation without any additional treatment. Utilizing only the starch in the flour would theoretically yield 425L ethanol per ton flour. By applying heat pretreatment to the water-insoluble material prior to enzymatic hydrolysis, the ethanol yield could be increased by 59L per ton flour, i.e. a 14% increase compared with starch-only utilization, assuming fermentation of the additional pentose and hexose sugars liberated.

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Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Chemical Engineering

Keywords

  • Cellulose, Starch, Bioethanol, Enzymatic hydrolysis, Pretreatment
Original languageEnglish
Pages (from-to)6505-6511
JournalBioresource Technology
Volume99
Issue number14
Publication statusPublished - 2008
Publication categoryResearch
Peer-reviewedYes

Bibliographic note

Available online 20 February 2008.