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

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Design and operation of a bench-scale process development unit for the production of ethanol from lignocellulosics. / Palmqvist, E; Hahn-Hägerdal, Bärbel; Galbe, Mats; Larsson, M; Stenberg, K; Szengyel, Z; Tengborg, C; Zacchi, Guido.

In: Bioresource Technology, Vol. 58, No. 2, 1996, p. 171-179.

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T1 - Design and operation of a bench-scale process development unit for the production of ethanol from lignocellulosics

AU - Palmqvist, E

AU - Hahn-Hägerdal, Bärbel

AU - Galbe, Mats

AU - Larsson, M

AU - Stenberg, K

AU - Szengyel, Z

AU - Tengborg, C

AU - Zacchi, Guido

PY - 1996

Y1 - 1996

N2 - 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.

AB - 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.

KW - ethanol production

KW - enzymatic process

KW - lignocellulosics

KW - willow

KW - steam

KW - treatment

KW - inhibitors

KW - waste-water recycling

U2 - 10.1016/S0960-8524(96)00096-X

DO - 10.1016/S0960-8524(96)00096-X

M3 - Article

VL - 58

SP - 171

EP - 179

JO - Bioresource Technology

JF - Bioresource Technology

SN - 0960-8524

IS - 2

ER -