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Effect of the dissolved oxygen on the bioproduction of glycerol and ethanol by Hansenula anomala growing under salt stress conditions

Paper ID Volume ID Publish Year Pages File Format Full-Text
25240 43562 2006 9 PDF Available
Title
Effect of the dissolved oxygen on the bioproduction of glycerol and ethanol by Hansenula anomala growing under salt stress conditions
Abstract

The effect of the dissolved oxygen on glycerol and ethanol productions by an osmotolerant yeast Hansenula anomala was examined during growth in media at low water activity resulting from the addition of 2 M NaCl in the culture medium. High stirring rate, high culture medium aeration, as well as high mass transfer surface inhibited both glycerol and ethanol biosynthesis. In absence of oxygen, yeast used acetaldehyde as a hydrogen acceptor, leading to the stimulation of ethanol biosynthesis and accounting for the low biomass and glycerol production; the experimental ratio ethanol on glycerol produced was 5.1 when the available oxygen was lowered (low stirring rate, 500 rpm) and increased to 10.2 in absence of aeration. Extracellular glycerol production was therefore optimal for a moderate stirring (1000 rpm) and aeration (1.4 vvm) rates. These optimal conditions resulted in an experimental ratio ethanol on glycerol produced of 4.1, namely close to the theoretical value of 4, illustrating the osmodependent channelling of carbon towards polyols production.

Keywords
Hansenula anomala; Glycerol production; Ethanol production; Cell maintenance; Dissolved oxygen
First Page Preview
Effect of the dissolved oxygen on the bioproduction of glycerol and ethanol by Hansenula anomala growing under salt stress conditions
Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Biotechnology - Volume 125, Issue 1, 20 August 2006, Pages 95–103
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering