Production of succinate from simply purified crude glycerol by engineered Escherichia coli using two-stage fermentation

Bioresources and Bioprocessing

Table 2 Comparison of glycerol consumption and succinate production in different culture in 1.5-L bioreactor

Culture	B-1	B-2	B-3
Aerobic stage
Carbon sources (g/L)	Glycerol 50^a; ammonium acetate 10	Glycerol 50^b; ammonium acetate 10	Glycerol 50^c; ammonium acetate 10
Time (h)	38	36	28
Aeration rate in induction stage (vvm)	1.5	1.5	1.5
μ_max (batch)/(h)	0.184	0.203	0.211
Maximum cell concentration (g DCW/L)	10.9	10.6	7.7
Anaerobic stage
Time (h)	93	95	103
Final concentration of succinate (mmol/L)	50.3	566.0	615.9
Final concentration of acetate (mmol/L)	30.3	20.8	8.6
Glycerol consumption (mmol/L)	54.1	583.3	702.8
Average specific succinate productivity (μmol g/DCW/h)	49.6	562.0	773.2
Average specific glycerol consumption rate (μmol g/DCW/h)	53.3	579.3	882.4
Yield of succinate in anaerobic stage (mol/mol)	0.93	0.97	0.88

The anaerobic stage lasted 72 h
^aCrude glycerol without simple purification was used as carbon source and the concentration of glycerol reached 50 g/L
^bSimply purified crude glycerol was used as carbon source and the concentration of glycerol reached 50 g/L
^cPure glycerol concentration reached 50 g/L