Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
240269 | Procedia Chemistry | 2015 | 8 Pages |
The ethanol production by recombinant Escherichia coli introducing of pyruvate decarboxylase (pdc) and alcohol dehydrogenase (adhB) from Zymomonas mobilis was investigated under aerobic conditions. In aerobic culture (KLa = 1.5 min-1), the cells expressing pdc and adhB produced 0.4 g l-1 ethanol when cultured for 18 h. This value was improved in BW25113Δpta/pHfdh/pTadhB-pdc following 4 g l-1 formate feeding at 0.8 g l-1 ethanol. In higher oxygenation level (KLa = 6.1 min-1), the production of ethanol was further enhanced at 1.79 g l-1 ± 0.37 g l-1 after 24 h cultivation. Formate was found not detectable at the end of culture, indicating complete degradation this organic acid to regenerate NADH from NAD+. The culture strategy was effective to inactivate lactate dehydrogenase, which is major competitor for ethanol production in utilizing NADH.