Coexpression of two essential isobutanol synthesis genes in Escherichia coli

Abstract:

[Objective] E. coli DH5α modified the valine biosynthesis pathway to biosynthesize isobutanol. [Methods] The 2-ketoisovalerate decarboxylase gene (kivD) and alcohol dehydrogenase gene (adhA) of Lactococcus lactis 1.2829 were tandemly cloned and expressed in E. coli DH5α. [Results] The yield of isobatanol by the engineered E. coli was only 0.12 g/L by 24?h fermentation. Further results revealed that the insufficient KivD activity is the bottleneck for the isobutanol biosynthesis. A series of experiments also showed that the optimal temperature and pH for both KivD and AdhA are 30 °C and pH 6.5, respectively. [Conclusion] Isobatanol fermentation by cloning and expressing essential genes in host is feasible.

Key words:2-Ketoisovalerate decarboxylase, Alcohol dehydrogenase, E. coli DH5α, Isobutanol