Adaptive Laboratory Evolution (ALE) of Burkholderia sacchari for optimized growth rate on glycerol

• Grant number: 24/20666-8
• Support Opportunities: Scholarships abroad - Research Internship - Scientific Initiation
• Start date: March 31, 2025
• End date: July 30, 2025
• Field of knowledge: Biological Sciences - Microbiology - Applied Microbiology
• Principal Investigator: Luiziana Ferreira da Silva
• Grantee: Rodrigo Santos Martines
• Supervisor: Solange Ines Mussatto Dragone
• Host Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Institution abroad: Technical University of Denmark (DTU), Denmark
• Associated to the scholarship: 24/07659-2 - Evaluating Burkholderia sacchari growth and bioproducts generation from glycerol, BP.IC

Abstract

More than 640,000 m³ of glycerol was generated in Brazil in 2023 as a byproduct of the biodiesel industry, due to the increasing legal demand for its addition to diesel. A very useful application for glycerol, in the context of bio and circular economy, would be the production of bioplastics, such as polyhydroxyalkanoates (PHA) - biodegradable and biocompatible bacterial polyesters, which are an alternative to petrochemical ones. Considering that in the economic scenario the substrate is the factor that most affects the overall cost of the PHA production process, the use of glycerol presents an excellent opportunity to eliminate this barrier, while adding value to a byproduct by using it as a raw material. For this goal, it is essential to have microorganisms recognized as good PHA producers that can utilize glycerol. The bacterium Burkholderia sacchari, known to be capable of accumulating PHA, has been studied as a potential chassis for various synthetic biology approaches, being able to consume a range of carbon sources. However, the consumption efficiency for glycerol is low: the OD600 does not even reach 0.5 after 48 hours of cultivation (preliminary studies). A similar observation was made for Cupriavidus necator, grown under similar conditions, for which evolutionary engineering generated clones capable of reaching OD600 = 1 in 17 hours, starting from an equivalent wildtype strain inoculum that took 110 hours. Furthermore, literature data on glycerol consumption by B. sacchari present inaccuracies, as they measure the efficiency of glycerol not as a single carbon source , but combined with other carbon sources; therefore, more studies need to be conducted. Thus, this project aims to increase the rate of glycerol consumption and PHA production by B. sacchari using adaptive evolution.