Poster abstracts

Poster number 85 submitted by Ehab Ammar

Cloning and Functional Analysis of Constitutive Promoters from Propionibacterium acidipropionici ATCC 4875

Ehab M. Ammar (Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, Ohio, USA), Chunxiao Zhangb (College of Bioscience and Bioengineering, Hebei University, China), Shang-Tian Yang (Department of Chemical and Biomolecular Engineering, The Ohio State University, Columbus, Ohio, USA)

Abstract:
Propionic acid is commonly used as a chemical intermediate in various manufacturing processes, and its salts are widely used as food preservatives. Currently, it is produced via petrochemicals which are neither economic nor environment-friendly, and that is why there is growing interest in its production by fermentation. Metabolic engineering of the biosynthetic pathway in the producer microorganism(Propionibacteria acidipropionici) is a newly investigated route to enhance fermentative production in this host. A major obstacle to this approach is that not much is known about the genetics of this bacterium. Promoters are key players in metabolic engineering as they influence gene expression levels. In our search for strong promoters, 11 plasmids with promoters from P. acidipropionici ATCC 4875 were constructed based on a vector with a promoterless reporter gene (pTD210) and then transformed into the host. Promoter strengths were analyzed as a function of b-galactosidase activity. Results showed that investigated promoters drove the reporter gene expression to different levels, both in P. acidipropionici and E. coli; however, activities in these two hosts were not closely correlated. Moreover, there were no distinct sequence similarities among these promoter sequences. Potential strong promoters found in this study would enhance future fermentative production of propionic acid.

References:
1- Faye, T., Asebo, A., Salehian, Z., Langsrud, T., Nes, I. F. and Brede, D. A. (2008) Construction of a reporter vector system for in vivo analysis of promoter activity in Propionibacterium freudenreichii. Appl Environ Microbiol 74: 3615-3617.

2- Piao, Y., Kawaraichi, N., Asegawa, R., Kiatpapan, P., Ono, H., Yamashita, M. and Murooka, Y. (2004) Molecular analysis of promoter elements from Propionibacterium freudenreichii. J Biosci Bioeng 97: 310-316.

Keywords: Propionibacteria acidipropionici, promoter, b-galactosidase