A novel high-throughput method for kinetic characterisation of anaerobic bioproduction strains, applied to Clostridium kluyveri

• Published in: Scientific reports Vol. 8; no. 1; pp. 9724 - 13
• Main Authors: Candry, Pieter, Van Daele, Timothy, Denis, Kyrina, Amerlinck, Youri, Andersen, Stephen J., Ganigué, Ramon, Arends, Jan B. A., Nopens, Ingmar, Rabaey, Korneel
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 27-06-2018; Nature Publishing Group
• Subjects: 631/1647/2234; 631/326/2522; 631/61/168; Acetic acid; Acids; Antimicrobial agents; Butyric acid; Clostridium; Data collection; Data processing; Ethanol; Growth kinetics; Growth rate; Humanities and Social Sciences; multidisciplinary; Saturation index; Science; Science (multidisciplinary); Toxicity
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-018-27594-9

Hexanoic acid (HA), also called caproic acid, can be used as an antimicrobial agent and as a precursor to various chemicals, such as fuels, solvents and fragrances. HA can be produced from ethanol and acetate by the mesophilic anaerobic bacterium
Clostridium kluyveri
, via two successive elongation steps over butyrate. A high-throughput anaerobic growth curve technique was coupled to a data analysis framework to assess growth kinetics for a range of substrate and product concentrations. Using this method, growth rates and several kinetic parameters were determined for
C
.
kluyveri
. A maximum growth rate (µ
max
) of 0.24 ± 0.01 h
−1
was found, with a half-saturation index for acetic acid (K
S,AA
) of 3.8 ± 0.9 mM. Inhibition by butyric acid occurred at of 124.7 ± 5.7 mM (K
I,BA
), while the final product, HA, linearly inhibited growth with complete inhibition above 91.3 ± 10.8 mM (K
HA
of 10.9*10
−3
 ± 1.3*10
−3
 mM
−1
) at pH = 7, indicating that the hexanoate anion also exerts toxicity. These parameters were used to create a dynamic mass-balance model for bioproduction of HA. By coupling data collection and analysis to this modelling framework, we have produced a powerful tool to assess the kinetics of anaerobic micro-organisms, demonstrated here with
C
.
kluyveri
, in order further explore the potential of micro-organisms for chemicals production.