Design and operation of a bench-scale process development unit for the production of ethanol from lignocellulosics

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title = "Design and operation of a bench-scale process development unit for the production of ethanol from lignocellulosics",
abstract = "A bench-scale unit for the development of an enzymatic process for the bioconversion of lignocellulosics to ethanol has been used to study the recycling of waste-water streams to minimize fresh-water requirements and reduce effluent streams. Willow, after impregnation with sulphur dioxide, was steam-pretreated, enzymatically hydrolysed, and the sugars produced were fermented using S. cerevisiae. The fermentation broth was distilled and the stillage was fractionated by evaporation into six separate condensate fractions and a residue. The overall yield of ethanol from willow was 65{\%} of the theoretical yield based on total fermentable sugars. The inhibitory effect of the evaporation condensates was assessed by fermentation using S. cerevisiae. The non-volatile residue of the stillage was found to be inhibitory to fermentation. The ethanol yield decreased from 0.37 g/g in a pure sugar reference to 0.31 g/g in the residue and the average ethanol fermentation rate decreased fi om 6.3 g/(l h) to 2.7 g/(l h), respectively. The evaporation condensates, containing the volatile components, showed no negative effects on fermentation. The intermediate evaporation condensate fractions, fractions 4 and 5, had the lowest chemical oxygen demand (GOD), 1560 and 1120 mg/l, compared with 33 300 mg/l for the stillage. Therefore, these fractions can be released directly into the effluent without further treatment. Copyright (C) 1997 Elsevier Science Ltd.",
keywords = "ethanol production, enzymatic process, lignocellulosics, willow, steam, treatment, inhibitors, waste-water recycling",
author = "E Palmqvist and B{\"a}rbel Hahn-H{\"a}gerdal and Mats Galbe and M Larsson and K Stenberg and Z Szengyel and C Tengborg and Guido Zacchi",
year = "1996",
doi = "10.1016/S0960-8524(96)00096-X",
language = "English",
volume = "58",
pages = "171--179",
journal = "Bioresource Technology",
issn = "0960-8524",
publisher = "Elsevier",
number = "2",