Study of genes involved in beta-oxidation to increase the efficiency in converting substrate to 3-hydroxyhexanoate in the production of poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) P(3HB-co-3HHx) by B. sacchari

• Grant number: 13/06112-5
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: July 01, 2013
• End date: January 31, 2014
• Field of knowledge: Biological Sciences - Microbiology - Applied Microbiology
• Principal Investigator: Luiziana Ferreira da Silva
• Grantee: Thatiane Teixeira Mendonça
• Supervisor: Christopher T. Nomura
• Host Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: State University of New York, Oswego (SUNY), United States

Abstract

The copolymer poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) P(3HB-co-3HHx) presents interesting mechanical and physical properties of industrial viewpoint. Variations in the amounts of monomer 3HHx result in different characteristics and application possibilities. Burkholderia sacchari is a bacterium capable of producing P(3HB-co-3HHx) at levels up to 2 mol% 3HHx from glucose and hexanoic acid. To increase the content of monomer in the copolymer produced by this microorganism were constructed recombinant strains containing genes of Aeromonas sp. These recombinants were capable of producing up to 26 mol% 3HHx. According to the hexanoic acid concentrations provided, the values of conversion of monomers in 3HHx hexanoic acid were less than 50% of the theoretical maximum which could be reached (0.98 g/g). With the aim to achieve a better conversion efficiency acid hexanóico/3HHx intended to promote a greater intermediates C6 direction for them to be incorporated into the copolymer. To this will be introduced directed mutations in specific genes the ²-oxidation of fatty acids in B. sacchari to inactivate them. This will be done by homologous recombination using the suicide vector pNPTS138. The mutants obtained will be subjected to experiments in shaken flasks supplying with glucose/hexanoic acid in different proportions. Then, it will be evaluated the ability of accumulation PHA, waiting thus achieve greater efficiencies of conversion of substrate/product. (AU)