Adaptive laboratory evolution of the PHB-producing Synechocystis sp. PCC6803 for improved acetate consumption

• Grant number: 23/07986-0
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: January 01, 2024
• Status: Discontinued
• Field of knowledge: Agronomical Sciences - Food Science and Technology - Food Engineering
• Principal Investigator: Cassius Vinicius Stevani
• Grantee: Dielle Pierotti Procópio
• Host Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated scholarship(s): 24/05662-6 - Metabolic Engineering of the acetate-evolved Synechocystis sp. B12 for improved PHB production, BE.EP.PD

Abstract

The cyanobacterium Synechocystis sp. PCC6803 has emerged as an efficient producer of a special derivative of polyhydroxyalkanoates (PHA), poly(3-hydroxybutyrate) (PHB). This remarkable property holds significant potential for biotechnological applications, particularly in the realm of directly deriving PHB from CO2 and CO2-derived acetate, which will be obtained from the Hybrid Electrosynthesis of Values-Added Chemicals - HELVA Consortium (FAPESP 2022/07645-6). These innovative processes offer a significant opportunity to mitigate atmospheric carbon dioxide concentration, thereby tackling the urgent challenges posed by global warming and air pollution. Building upon the manifold advantages of microorganisms adept at optimizing acetate consumption for biotechnological purposes, our study seeks to enhance the uptake of acetate in Synechocystis sp. PCC6803. To achieve this, we will cultivate the cyanobacterium in a chemostat, employing an acetate-containing medium. By gradually increasing the dilution rates, we aim to refine the kinetics of acetate consumption. We expect that this approach will yield an evolved strain of Synechocystis sp. PCC6803 showcases superior growth characteristics in the presence of higher acetate levels than those supported by the parental strain. Moreover, we expect this strain to exhibit an elevated PHB bioaccumulation content. By optimizing acetate consumption in Synechocystis sp. PCC6803, we anticipate an enhanced acetyl-CoA pool, leading to increased acetoacetyl-CoA levels and activation of the PHA biosynthetic pathway. To delve deeper into the genetic and transcriptomic changes associated with the improved acetate uptake, the strain demonstrating the most favorable phenotype will undergo DNA and RNA sequencing, unveiling crucial insights into the underlying mechanisms driving these enhancements.