Ethanol Production in Actinomycetes after Expression of Synthetic adhB and pdc

Abstract

Streptomyces strains are producing many important secondary metabolites, in many cases used as pharmaceutical drugs. Though the usage of these bacteria for the production of fuel has never been described. We could show, that the expression of two artificial ethanologenic genes of Zymomonas mobilis in different actinomycetes strains resulted in the production of ethanol. The synthetic genes adhB and pdc encoding an alcohol dehydrogenase and a pyruvate decarboxylase, respectively, were expressed in eight different Streptomyces strains. Best production was obtained using Streptomyces coelicolor A3(2) harboring both genes. By variation of the cultivation conditions, the amount of ethanol produced by the strain could be increased up to 2.6 g/l.

Enzymatic Decarboxylation—An Emerging Reaction for Chemicals Production from Renewable Resources

“…Typically, engineered strains of S. cerevisiae including the respective enzymes are used for this purpose. To improve the product yield of this well‐established process, attempts to improve the expression rates of PDC75 and to introduce heterologous PDC genes into alternative microbial hosts, such as Deinococcus radiodurans ,76 Lactococcus lactis ,77 Streptomyces coelicolor ,78 Sphingomonas sp.,79 or Enterococcus faecalis , have been performed 80. Adding to these classical fermentative approaches, several studies have been published in which PDCs and the corresponding alcohol dehydrogenases were introduced into photosynthetic organisms, which allows the direct conversion of CO 2 into ethanol 81.…”