Engineering Corynebacterium glutamicum for the production of 2,3-butanediol

Table 3 Glucose (Glc) consumption rate (GCR), molar yield and productivity of 2,3-butanediol (2,3-BD), and carbon recovery (CR) by the control and engineered C. glutamicum strains

	GCR (nmol min⁻¹ mg CDW⁻¹)	Yield (mol 2,3-BD per mol Glc)	Productivity (nmol min⁻¹ mg CDW⁻¹)	CR (%)
ΔldhA (pEKEx2)*	2.5 ± 0.4	0.05 ± 0.00^#	0.12 ± 0.01	81 ± 3
ΔldhA (pEKEx2- als,aldB,butA)*	4.4 ± 0.4	0.34 ± 0.04	1.28 ± 0.09	79 ± 9
ΔldhA (pEKEx2)	3.0 ± 0.2	0.02 ± 0.01^#	0.06 ± 0.03	77 ± 1
ΔldhA (pEKEx2- als,aldB,butA)	3.4 ± 0.4	0.27 ± 0.06	0.53 ± 0.13	82 ± 3
ΔaceEΔpqoΔldhA (pEKEx2)	1.6 ± 0.3	0.22 ± 0.01^#	0.30 ± 0.00	87 ± 1
ΔaceEΔpqoΔldhA (pEKEx2-als,aldB,butA)	5.4 ± 0.7	0.66 ± 0.05	3.55 ± 0.58	84 ± 7
ΔaceEΔpqoΔldhA (pEKEx2-als,aldB, _Ptuf butA)	6.1 ± 0.1	0.61 ± 0.06	3.13 ± 0.22	87 ± 3
ΔaceEΔpqoΔldhAΔmdh (pEKEx2)	1.6 ± 0.3	0.34 ± 0.05^#	0.53 ± 0.00	91 ± 6
ΔaceEΔpqoΔldhAΔmdh (pEKEx2-als,aldB,butA)	6.0 ± 0.3	0.64 ± 0.09	4.34 ± 0.16	90 ± 4
ΔaceEΔpqoΔldhAΔmdh (pEKEx2-als,aldB, _Ptuf butA)	6.5 ± 0.5	0.64 ± 0.10	4.25 ± 0.41	91 ± 7

In the first phase, cells were grown aerobically on 1 % (wt/vol) potassium acetate except for the strains indicated with an asterisk for which 0.5 % (wt/vol) glucose was used instead. Second phase fermentations were carried out for 48 h, using 25 mL of cell suspension in closed 50-mL falcon flasks with glucose as substrate. The cardinal symbol indicates that optically active 2,3-BD was produced; remaining strains produced meso-form of 2,3-BD. Values are averages of at least three independent experiments. A single NMR spectrum was acquired for each sample

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