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The kinetics of simultaneous glucose and fructose uptake and product formation by Aspergillus niger in citric acid fermentation

Paper ID Volume ID Publish Year Pages File Format Full-Text
36770 45146 2004 8 PDF Available
Title
The kinetics of simultaneous glucose and fructose uptake and product formation by Aspergillus niger in citric acid fermentation
Abstract

The kinetics of substrate uptake and product formation in the process of citric acid accumulation by Aspergillus niger on sucrose as a sole carbon source are presented. The experiments are aimed at studying if glucose and fructose obtained from the hydrolysis of sucrose are equivalent carbon sources for A. niger and how the presence of the two different carbon substrates might influence the citric acid formation process. Beet sugar was used as a sole carbon source in the first series of experiments conducted in two types of bioreactors: stirred tank and air-lift. The fructose uptake rate was significantly lower than the glucose uptake rate in the late idiophase. A substrate utilisation breakpoint occurred when a large amount of citric acid was accumulated in the fermentation broth. A similar phenomenon was also detected in repeated fed-batch fermentation. This phenomenon was confirmed by the second series of parallel shake culture runs, in which fungal growth and citric acid accumulation by A. niger was simultaneously tested on the media containing the following carbon sources: sucrose, glucose and fructose, with and without addition of concentrated citric acid solution. Finally, it was shown that high concentration of citric acid strongly depleted fructose uptake rate.

Keywords
Kinetics; Carbohydrates utilisation; Citric acid production; Aspergillus niger
First Page Preview
The kinetics of simultaneous glucose and fructose uptake and product formation by Aspergillus niger in citric acid fermentation
Publisher
Database: Elsevier - ScienceDirect
Journal: Process Biochemistry - Volume 39, Issue 12, 29 October 2004, Pages 2261–2268
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering