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Applied Biochemistry and Biotechnology

, Volume 43, Issue 3, pp 211–226 | Cite as

Production of fuel alcohol from wheat by VHG technology

Effect of sugar concentration and fermentation temperature
  • K. C. Thomas
  • S. H. Hynes
  • A. M. Jones
  • W. M. Ingledew
Article

Abstract

Very high gravity (VHG) wheat mashes containing more than 300 g of dissolved solids per liter were prepared and fermented with active dry yeast at 20, 25, 30, and 35°C with and without yeast extract as nutrient supplement. At 20°C, mashes with 38% (w/v) dissolved solids end-fermented without any nutrient supplementation and maximum ethanol yields of 23.8% (v/v) were obtained. With increasing temperatures, the sugar consumption decreased. Addition of yeast extract stimulated the rate of fermentation at all temperatures, but did not increase the total amount of sugar consumed. The stimulatory effect of yeast extract on cell multiplication decreased with increasing sugar concentration, and virtually no difference in cell number was observed between yeast extract-supplemented and unsupplemented mashes at sugar concentrations above 33% (w/v). The fermentative capacity of the yeast (expressed as maximum specific rate of sugar consumption) remained the same at all sugar concentrations in unsupplemented mashes, but decreased in yeast extract-supplemented mashes at sugar concentrations below 33% (w/v). When the sugar concentration was above 33% sugar (w/v), the fermentative capacity in yeast extract-supplemented mashes was greater than that observed in unsupplemented samples.

Index Entries

Fuel alcohol very high gravity fermentation technology VHG fermentation temperature fermentative capacity yeast cell viability 

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Copyright information

© Humana Press Inc. 1993

Authors and Affiliations

  • K. C. Thomas
    • 1
  • S. H. Hynes
    • 1
  • A. M. Jones
    • 1
  • W. M. Ingledew
    • 1
  1. 1.Department of Applied Microbiology and Food ScienceUniversity of SaskatchewanSaskatoonCanada

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