title: Hydrodynamic chronoamperometry for probing kinetics of anaerobic microbial metabolism--case study of Faecalibacterium prausnitzii.
abstract: Monitoring in vitro 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, 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 × 10(4) to 5 × 10(7) cells.mL(-1)). Apparent Michaelis-Menten kinetics was observed with respect to riboflavin (KM = 6 μM; kcat = 5.3 × 10(5) s(-1), at 37 °C) and glucose (KM = 6 μM; kcat = 2.4 × 10(5) s(-1)). The short temporal resolution allows continuous monitoring of fast cellular events such as kinetics inhibition with butyrate. Furthermore, we detected for the first time riboflavin reduction by another potential probiotic, Butyricicoccus pullicaecorum. The ability of the RDE for fast, accurate, simple and continuous measurements makes it an ad hoc tool for assessing bioprocesses at high resolution.
authors.affiliation: Laboratory of Microbial Ecology and Technology, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium.
authors.forename: Antonin
authors.initials: A
authors.lastname: Prévoteau
authors.affiliation: Laboratory of Microbial Ecology and Technology, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium.
authors.forename: Annelies
authors.initials: A
authors.lastname: Geirnaert
authors.affiliation: Laboratory of Microbial Ecology and Technology, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium.
authors.forename: Jan B A
authors.initials: JBA
authors.lastname: Arends
authors.affiliation: University of Coimbra, Department of Electrical Engineering - Instituto de Telecomunicações, Coimbra 3030-290, Portugal.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Lannebère
authors.affiliation: Laboratory of Microbial Ecology and Technology, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium.
authors.forename: Tom
authors.initials: T
authors.lastname: Van de Wiele
authors.affiliation: Laboratory of Microbial Ecology and Technology, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium.
authors.forename: Korneel
authors.initials: K
authors.lastname: Rabaey
mesh_terms: D000693:Anaerobiosis; D015169:Colony Count, Microbial; D004563:Electrochemistry / Q000379:methods*; D004566:Electrodes; D005947:Glucose / Q000378:metabolism; D006094:Gram-Positive Bacteria / Q000378:metabolism*; D057446:Hydrodynamics; D007700:Kinetics; D015203:Reproducibility of Results; D012256:Riboflavin / Q000378:metabolism; D013997:Time Factors
chemical_list: D005947:Glucose; D012256:Riboflavin