Characterization of PHB production from waste materials using photosynthetic bacteria

• Grant number: 12/17183-8
• Support Opportunities: Scholarships abroad - Research Internship - Master's degree
• Start date: October 26, 2012
• End date: April 25, 2013
• Field of knowledge: Biological Sciences - Microbiology - Applied Microbiology
• Principal Investigator: Luiziana Ferreira da Silva
• Grantee: Débora Vieira Parrine Sant'Ana
• Supervisor: Patrick C. Hallenbeck
• Host Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: Université de Montréal, Canada
• Associated to the scholarship: 11/04454-0 - Analysis of metabolic flux applied to the biosynthesis of the biodegradable polymer poly-3-hydroxybutyrate (P3HB) by Burkholderia sacchari., BP.MS

Abstract

Biodegradable polymers produced by microorganisms appeared as a promising solution to environmental problems caused by synthetic plastics. Within this group of materials are the polyhydroxyalkanoates (PHA), polymers accumulated by microorganisms to be used as carbon reserve, stored in the cell under limitation of nutrients such as nitrogen or phosphorus. The PHA can be applied in the production of biodegradable plastics and biocompatible and biodegradable elastomers. Its applications are found in several areas, including: agroindustrial, biomedical and packaging industry. The microorganisms metabolize the degradation products of this polymer to water and carbon dioxide. The microbial electrosynthesis is a process that uses electrons derived from one electrode to reduce carbon dioxide into multiple carbon products. The objective of this project is to perform the electrosynthesis of PHB using a mutant strain of Rhodobacter capsulatus carrying the foxEYZ operon that confers an increased capacity for oxidation of Fe (II) light-dependent. To be able to achieve high yields of PHB we will study different parameters of continuous culture, such as: carbon source (glycerol and molasses cane sugar), substrate level, limitation in nitrogen level and light intensity. These will be evaluated by DOE (Design of Experiments) and RSM (Response Surface Methodology). A PV device will be used for reduction of carbon dioxide and water, producing organic compounds. If positive results are obtained, this will be the first demonstration of production of PHB by electrosynthesis. (AU)