A novel strategy for anaerobic production of polyhydroxyalkanoates (PHAs)

• Grant number: 19/07002-5
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: August 01, 2019
• End date: January 31, 2020
• Field of knowledge: Biological Sciences - Microbiology - Applied Microbiology
• Agreement: Netherlands Organisation for Scientific Research (NWO)
• Principal Investigator: Jonas Contiero
• Grantee: Paulo Marcelo Avila Neto
• Host Institution: Instituto de Pesquisa em Bioenergia (IPBEN). Universidade Estadual Paulista (UNESP). Campus de Rio Claro. Rio Claro , SP, Brazil
• Associated research grant: 17/50249-6 - A novel strategy for anaerobic production of polyhydroxyalkanoates (PHA), AP.TEM

Abstract

Although it is undeniable the contribution of oil-based plastics to the modernization of several technologies, the use of plastics in a disposable manner has caused serious pollution problems in marine and terrestrial habitats, and the exploitation of non-renewable carbon sources puts human existence at risk with the resulting climatic changes. It is necessary to replace recalcitrant plastics with alternatives made from biological origin, renewable sources, and with high biodegradability. In this context, polyhydroxyalkanoates (PHAs) is an option that is produced by many microorganisms. However, the large-scale production of PHAs is not yet economically inexpensive compared to the price of oil-based plastic. New technologies are addressed in this project to make PHA production viable by the application of metabolic engineering coupled with the adaptive laboratory evolution of Escherichia coli. Here we propose the synthesis of PHAs from sucrose in anaerobic fermentation, with better ATP gains by sucrose phosphorylation and better redox balance in anaerobiosis by the use of a NADH-dependent acetoacetyl-CoA reductase, making the PHA synthetized the final electron acceptor. Furthermore, competitive metabolic pathways will be eliminated or regulated to ensure that the prevailing fermentative route is the production of PHAs. Without aeration, the bioprocess becomes less expensive, and with the use of sucrose (sugarcane molasses) or even agro industrial residues, the production of this biopolymer can be cheapened to become competitive in the market.