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

Table 4 Glucose (Glc) consumption rate (GCR), molar yield and productivity of 2,3-butanediol (2,3-BD), and carbon recovery (CR) achieved with C. glutamicum ΔaceEΔpqoΔldhA(pEKEx2-als,aldB, _Ptuf butA) and C. glutamicum ΔaceEΔpqoΔldhAΔmdh(pEKEx2-als,aldB, _Ptuf butA) strains under different aeration conditions

	Airflow (mL min⁻¹)	GCR (nmol min⁻¹ mg CDW⁻¹)	Yield (mol 2,3-BD per mol Glc)	Productivity (nmol min⁻¹ mg CDW⁻¹)	CR (%)
ΔaceEΔpqoΔldhA (pEKEx2-als,aldB, _Ptuf butA)	5	7.2 ± 0.6	0.44 ± 0.04	3.4 ± 0.3	89 ± 6
	10	15.8 ± 1.7	0.57 ± 0.03	8.1 ± 0.4	91 ± 4
	20	14.7 ± 1.1	0.36 ± 0.06	5.0 ± 0.9	83 ± 10
ΔaceEΔpqoΔldhAΔmdh (pEKEx2-als,aldB, _Ptuf butA)	5	11.1 ± 1.0	0.52 ± 0.03	5.5 ± 0.7	85 ± 2
	10	21.1 ± 0.8	0.66 ± 0.01	10.9 ± 1.8	90 ± 8
	20	22.8 ± 1.6	0.46 ± 0.02	8.0 ± 0.7	78 ± 7

Cells were grown aerobically on 1 % (wt/vol) potassium acetate. The second, production phase was performed in a 80-mL fermenter at 30 °C for 30 h with glucose as substrate. The cell suspension was sparged with air at the flow rates indicated. Meso-2,3-BD was by far the major stereoisomer. At the optimal aeration rate (10 mL min⁻¹), there was 95 % of the meso-form. Values are averages of three independent experiments; a single NMR spectrum was acquired for each sample

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