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A rapid method for an offline glycerol determination during microbial fermentation
Kuhn, Jennifer; Müller, Hagen; Salzig, Denise & Czermak, Peter
Abstract
Background: The purpose of this work was to find a rapid method for glycerol detection during microbial
fermentations. The method requirements were, first, to avoid sample pretreatment, and second, to measure
glycerol precisely especially out of fermentation broth.
Results: This was achieved by combining two reaction principles — the Malaprade reaction and the Hantzsch
reaction. In the Malaprade reaction, glycerol is converted into formaldehyde. This forms a dye in the Hantzsch
reaction after which adsorption is than detected. The subsequent assay was investigated with two different
fermentation media, a chemically undefined and a chemically defined media, used for Pichia pastoris
fermentation. In both media, as well as in real fermentation samples, glycerol content could be reproducibly
detected with the method. Moreover, measurements were more precise than using a standard glycerol
detection kit.
Conclusions: With this rapid assay, glycerol could be detected easily in microbial fermentation broth. It is reliable
over a wide concentration range including advantages such as an easy assay set-up, a short assay time and no
sample pretreatment.
Keywords
Glycerol determination; Fermentation broth; Hantzsch reaction; Malaprade reaction
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