Time-resolved amino acid uptake of Clostridium difficile 630Δerm and concomitant fermentation product and toxin formation

Table 3 Exported metabolites detected in growth with CDMM

Product	t_{first detection}	t_{halfmaximal production}	Maximal relative production rate
	min	min	h⁻¹
Isovalerate	60	83 ± 5	0.59 ± 0.02
Propanoate	80	120 ± 8	0.39 ± 0.01
2-oxo-isocaproate	90	155 ± 12	0.26 ± 0.08
(4-hydroxyphenyl)acetate	150	161 ± 12	0.39 ± 0.04
5-aminovalerate	60	163 ± 7	0.33 ± 0.03
2-methylbutanoate	60	168 ± 13	0.45 ± 0.05
Acetate	90	175 ± 6	0.30 ± 0.02
3-(4-hydroxyphenyl)lactate	175	181 ± 5	0.78 ± 0.14
Isocaproate	60	194 ± 7	0.47 ± 0.05
Isobutanoate	60	202 ± 5	0.59 ± 0.04
Ammonium	traces in medium	210 ± 28	0.19 ± 0.04
2-aminobutanoate	150	213 ± 6	0.28 ± 0.02
Formate	60	228 ± 10	0.24 ± 0.01
Phenylacetate	60	231 ± 4	0.38 ± 0.03
Ethanol	210	259 ± 6	0.32 ± 0.04
3-hydroxybutanoate	240	261 ± 7	0.62 ± 0.13
p-cresol	60	263 ± 9	0.26 ± 0.02
2-hydroxybutanoate	150	273 ± 4	0.30 ± 0.03
1-butanol	225	274 ± 9	0.39 ± 0.03
Isobutanol	240	276 ± 8	0.46 ± 0.03
Butanoate	175	285 ± 6	0.30 ± 0.04
Valerate	175	315 ± 4	0.25 ± 0.06
3-phenylpropanoate	175	355 ± 9	0.21 ± 0.06
Lactate	225	364 ± 3	0.27 ± 0.02
3-phenyllactate	120	387 ± 21	0.12 ± 0.01

All compounds with the exception of formate and ammonium were detected by GC-MS; formate and ammonium were quantified by enzymatic assays (see Methods), total sampling range up to 660 min, for detailed fits, see Additional file 3

ISSN: 1471-2180