Characterization of volatile fatty-acid utilization in Escherichia coli aiming for robust valorisation of food residues

AMB Express

Table 2 Summary of values from chemostat cultivations of W3110 ΔFadR on a defined minimal salts medium with a mix of VFAs as carbon source

	mmol g⁻¹ h⁻¹	mmol DR^a g⁻¹ h⁻¹	mmol g⁻¹ h⁻¹	mmol DR^a g⁻¹ h⁻¹
q_{Acetic acid}	0.38 ± 0.05	3.0 ± 0.4	2.1 ± 0.2	16 ± 1
q_{Propionic acid}	0.051 ± 0.003	0.72 ± 0.04	0.24 ± 0.03	3.4 ± 0.4
q_{Butyric acid}	0.08 ± 0.02	1.5 ± 0.3	ND^b	ND^b
q_{Isovaleric acid}	0.009 ± 0.002	0.25 ± 0.06	ND^b	ND^b
q_{Valeric acid}	0.025 ± 0.003	0.66 ± 0.08	ND^b	ND^b
q_{Caproic acid}	0.57 ± 0.08	18 ± 2	0.46 ± 0.05	15 ± 1
q_{Total VFA}	4.8 ± 0.6 ^c	24 ± 3	7.6 ± 0.6 ^c	35 ± 4

The medium composition was designed from measurements of an anaerobic digest of food residues
Averages ± standard deviations. n = 6 (biological triplicates each sampled at two different timepoints separated by at least 1/D hours)
D denotes the chemostat dilution rate; q is the specific consumption rate of the indicated compound
(a) degree of reduction (Heijnen 1994)
(b) no significant consumption detected
(c) mmol carbon g⁻¹ h⁻¹