Metabolic engineering of Escherichia coli for l-malate production anaerobically

Table 1 Results of dual-phase fermentations of the recombinant strains in sealed bottles after 48 h

Strain^a	Consumed glucose (g/L)	Fermentation product titer (g/L)			Malate yield^b (g/g)
Strain^a	Consumed glucose (g/L)	Pyruvate	Succinate	Malate	Malate yield^b (g/g)
BA040	8.50 ± 0.24	0.97 ± 0.02	1.23 ± 0.02	1.73 ± 0.04	0.20 ± 0.01
BA041	10.50 ± 0.42	1.85 ± 0.08	2.46 ± 0.05	3.53 ± 0.25	0.34 ± 0.01
BA042	14.50 ± 0.20	2.52 ± 0.15	1.87 ± 0.08	4.39 ± 0.12	0.30 ± 0.01
BA050	9.50 ± 0.50	1.81 ± 0.21	1.58 ± 0.01	3.22 ± 0.36	0.34 ± 0.01
BA051	11.50 ± 0.50	1.69 ± 0.50	1.46 ± 0.02	5.30 ± 0.50	0.46 ± 0.50
BA052	10.00 ± 0.45	0.58 ± 0.01	1.85 ± 0.05	4.39 ± 0.21	0.44 ± 0.01
BA061	15.00 ± 0.42	2.87 ± 0.22	1.79 ± 0.02	9.39 ± 0.42	0.63 ± 0.01
BA062	15.00 ± 0.55	2.89 ± 0.14	1.45 ± 0.01	9.19 ± 0.55	0.61 ± 0.01
BA063	18.00 ± 0.46	2.67 ± 0.15	1.25 ± 0.02	13.14 ± 0.35	0.73 ± 0.01

Fermentations were carried out in a 100 mL sealed bottle with 30 ml LB medium with 30 g/L glucose and 16 g/L magnesium carbonate hydroxide (37 °C, 170 rpm). Anaerobiosis was achieved during growth with added bicarbonate to ensure an atmosphere of CO₂
^aAll the strains were tested with a two-stagedual-phase process (aerobic cell growth and anaerobic L-malate production), average fermentation characteristics from triplicate sealed bottle fermentations are shown
^b Yield was calculated as grams of L-malate produced per gram of glucose consumed

ISSN: 1475-2859