Improving 3-hydroxypropionic acid production in E. coli by in silico prediction of new metabolic targets

Author(s)

Chaves, Gabriel Luz ; Batista, Raquel Salgado ; Cunha, Josivan de Sousa ; Oliveira, Davi Benedito ; da Silva, Mateus Ribeiro ; Deriggi Pisani, Graziele Fernanda ; Selistre-de-Araujo, Heloisa Sobreiro ; Zangirolami, Teresa Cristina ; da Silva, Adilson Jose

• Document type: Journal article
• Source: NEW BIOTECHNOLOGY; v. 72, p. 9-pg., 2022-10-25.

Abstract

3-Hydroxypropionic acid (3-HP) production from renewable feedstocks is of great interest in efforts to develop greener processes for obtaining this chemical platform. Here we report an engineered E. coli strain for 3-HP production through the beta-alanine pathway. To obtain a new strain capable of producing 3-HP, the pathway was established by overexpressing the enzymes pyruvate aminotransferase, 3-hydroxyacid dehydrogenase, and L-aspartate-1-decarboxylase. Further increase of the 3-HP titer was achieved using evolutionary optimizations of a genome-scale metabolic model of E. coli containing the adopted pathway. From these optimizations, three non -intuitive targets for in vivo assessment were identified: L-alanine aminotransferase and alanine racemase over -expression, and L-valine transaminase knock-out. The implementation of these targets in the production strain resulted in a 40% increase in 3-HP titer. The strain was further engineered to overexpress phosphoenolpyruvate carboxylase, reaching 0.79 +/- 0.02 g/L of 3-HP when grown using glucose. Surprisingly, this strain produced 63% more of the desired product when grown using a mixture of glucose and xylose (1:1, C-mol), and gene expression analysis showed that the cellular adjustment to consume xylose had a positive impact on 3-HP accumulation. Fed-batch culture with xylose feeding led to a final titer of 29.1 g/L. These results reinforce the value of computational methods in strain engineering, enabling the design of more efficient strategies to be assessed. Moreover, higher production of 3-HP under a sugar mixture condition points towards the development of bio-processes based on renewable resources, such as hemicellulose hydrolysates. (AU)

• FAPESP's process: 16/10636-8 - From the cell factory to the Biodiesel-Bioethanol integrated biorefinery: a systems approach applied to complex problems in micro and macroscales
• Grantee: Roberto de Campos Giordano
• Support Opportunities: Program for Research on Bioenergy (BIOEN) - Thematic Grants
• FAPESP's process: 19/07902-6 - Development of a microbial cell factory for 3-hydroxypropionic production
• Grantee: Gabriel Luz Chaves
• Support Opportunities: Scholarships in Brazil - Master