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Hydrodynamic chronoamperometry for probing kinetics of microbial metabolism

Boekbijdrage - Boekabstract Conferentiebijdrage

In vitro monitoring of the metabolic activity of microorganisms aids bioprocesses and enables better understanding of microbial metabolism. Redox mediators can be used for this purpose via different electrochemical techniques that are either complex or only provide non-continuous data. Hydrodynamic chronoamperometry using a rotating disc electrode (RDE) can alleviate these issues but was seldom used and is poorly characterized. The kinetics of Faecalibacterium prausnitzii A2-165 in suspension, a beneficial gut microbe, were determined using a RDE with riboflavin as redox probe. This butyrate producer anaerobically ferments glucose and reduces riboflavin whose continuous monitoring on a RDE provided highly accurate kinetic measurements of its metabolism, even at low cell densities. The metabolic reaction rate increased linearly over a broad range of cell concentrations (9×104 to 5×107 cells.mLU+22121, Figure 1(A)). Apparent Michaelis-Menten kinetics was observed with respect to riboflavin (KM = 6 µM; kcat = 5.3×105 sU+22121, at 37°C) and glucose (KM = 6 µM; kcat = 2.4×105 sU+22121). The short temporal resolution allows continuous monitoring of fast cellular events, such as kinetics inhibition with butyrate (Figure 1(B)). Furthermore, the high sensitivity of the technique allowed to detect for the first time the much slower riboflavin reduction by another potential probiotic, Butyricicoccus pullicaecorum (kcat = 8×103 sU+22121). The ability of the RDE for fast, accurate, simple and continuous measurements makes it an ad hoc tool for assessing bioprocesses at high resolution. Further development of this technique will allow understanding of product inhibitions and substrate affinities in bioelectrochemical systems.
Boek: International Society of Electrochemistry, 67th Annual meeting, Abstracts
Aantal pagina's: 1
Jaar van publicatie:2016
Toegankelijkheid:Open