Poster abstracts

Poster number 90 submitted by Ehab Ammar

Producing n-Propanol from metabolically engineered propionibacteria

Ehab Ammar (Chemical and Biomolecular Engineering), Shang-Tian Yang (Chemical and Biomolecular Engineering)

Abstract:
Propionibacteria are widely used in many industries including probiotics, vitamin B12, Swiss cheese and propionic acid production. Unfortunately, not much is known about the genetics of propionibacteria and hence there are few reports on manipulating their metabolic pathways. n-Propanol (a solvent, an intermediate in many pharmaceutical and industrial processes, and a biofuel) is currently produced from petrochemicals which are perishable and costly. No wild type microorganism is known to produce n-propanol in quantities that satisfy industrial applications. In this work, upon overexpressing a bifunctional aldehyde/alcohol dehydrogenase from E. coli in P. freudenreichii, mutants produced n-propanol from glucose. To overcome the limitation of reducing equivalents in the metabolic pathway, a more reduced carbon source was used leading to 60% increase in n-propanol final titre. Interestingly, the mutants also exhibited higher propionic acid productivity with up to %100 improvement. To the best of our knowledge, this is the first report on metabolic engineering of propionibacteria for n-propanol production. Also, it is a novel route for n-propanol production, and possibly a new approach for enhancing propionic acid production as well.

References:
EM Ammar,Z. Wang and ST Yang (2013) Metabolic engineering of Propionibacterium freudenreichii for n-propanol production. Appl Microbiol Biotechnol. (Published online ahead of print)

Keywords: Metabolic engineering, Propionibacteria, n-Propanol and Biofuel