Increased expression of xylA, xylB and tktA in B. sacchari to improve xylose consumption in bioplastic production

• Grant number: 24/07093-9
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: July 01, 2024
• End date: June 30, 2025
• Field of knowledge: Biological Sciences - Microbiology - Applied Microbiology
• Principal Investigator: Luiziana Ferreira da Silva
• Grantee: Juliana Amaral Bichler
• Host Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Currently, there is great effort to search for alternatives that can replace conventional plastics, such as polyhydroxyalkanoates (PHA), in order to minimize damage to the environment. PHAs are a family of biodegradable and biocompatible polyesters, produced on different scales through metabolic processes by different bacteria. However, the economic viability of industrial-scale production of these polymers is still limited due to the low efficiency of the process, which increases the high cost of production and raw materials. One of the possible strategies for reducing the cost of PHA production is the use of abundant and cheap raw materials, such as the use of lignocellulosic waste in the context of a biorefinery. Among the components of this waste, hemicellulose is composed especially of xylose, which currently imposes a barrier to the use of lignocellulosic waste due to the lack of efficiency in its conversion into metabolic processes and products. Burkholderia sacchari is capable of accumulating PHA in up to 80% of its dry mass and is capable of consuming xylose with high efficiency, presenting great potential for its implementation in biorefineries. Although efficient compared to other biotechnological platforms, there is still room to improve its use of xylose. Two previous studies, independently, were able to increase the consumption and specific growth rate of B. sacchari on xylose through the expression of xylose isomerase genes (xylA and xylB genes) and the pentose-phosphate pathway (tktA). The objective of this work is to express the genes involved in these pathways simultaneously and obtain a new recombinant B. sacchari, evaluating the effects of this expression on the performance of B. sacchari in terms of PHA accumulation and growth on xylose.