Increasing the production of (R)-3-hydroxybutyrate in recombinant Escherichia coli by improved cofactor supply

Table 2 Production of (R)-3-hydroxybutyrate by using strategies for increased NADPH availability

Process	Plasmids	Nitrogen source	Time (h)	CDW (g L⁻¹)	Glucose consumed (g L⁻¹)	3HB (g L⁻¹)	μ (h⁻¹)	r_{3HB average} (g L⁻¹ h⁻¹)	q_{3HB average} (mg g⁻¹ h⁻¹)	Y_3HB/Glc (g g⁻¹)	Y_3HB/CDW (g g⁻¹)	Reference
Unrestricted	pJBGT3RX	NH₄ ⁺	5.5	4.18	8.90	0.51	0.73	0.093	68	0.057	0.12	[16]
Unrestricted	pJBGT3RX	NH₄ ⁺ + glutamate	6.5	3.84	10.40	0.68	0.72	0.105	116	0.065	0.18	This study
Unrestricted	pJBGT3RX + pBADzwf	NH₄ ⁺	7.0	3.69	10.01	0.73	0.68	0.104	75	0.073	0.20	This study
N-depletion	pJBGT3RX	NH₄ ⁺	11.8	2.54	7.05	0.50	–	0.042	17	0.071	0.20	[15]
N-depletion	pJBGT3RX	NH₄ ⁺ + glutamate	11.9	2.39	7.75	0.55	–	0.046	35	0.071	0.23	This study
N-depletion	pJBGT3RX + pBADzwf	NH₄ ⁺	11.8	2.00	8.46	1.06	–	0.090	57	0.125	0.53	This study
N-Fedbatch	pJBGT3RX + pBADzwf	NH₄ ⁺	30.0	34.80	98.10	12.70	–	0.423	14	0.129	0.36	This study

In the cases of nitrogen depletion and fedbatch, q_3HB are calculated for the respective limited/depleted phase only, and do not include the excess-nutrients phase. Process names refer to: Unrestricted, means that all nutrients were supplied in the medium as regular batch cultivation. N-depletion, cultivation with two phases, a short batch with all nutrients in excess and a nitrogen depletion phase. N-Fedbatch, cultivation with two phases, a repeated batch where the nutrients were added repeated times to kept in excess and a nitrogen limitation fedbatch phase

ISSN: 1475-2859