DP_AEM student
Centro de Engenharia Biológica (CEB)
Doctoral Program in Chemical and Biological Engineering (CEB)
Joana Alves

Phd Thesis

A step forward in the development of a syngas-based biorefinery using the new acetogen A. wieringae strain JM

PD/BD/150583/2020 - Started at 01/02/2020

Synthesis gas (usually called syngas), mainly composed of carbon monoxide (CO), is a polluting gas produced by several industrial sectors as the end product of gasification process. Fermentation of syngas/CO by carboxidrotrophic microbes allows the production of compounds with high economical and industrial interest. The interest and need in implementing this technology at industrial level and expanding its production frame towards more complex products is increasing.

This PhD project follows on from the team's previous work combining new designs of fermenters suitable for gas fermentation and implementing a new acetogen, A. wieringae strain JM, as a platform for syngas-based biorefinery. This acetogen possesses unique capabilities to efficiently convert components of the synthesis gas, namely CO. However, gas fermentation still faces some challenges related mainly to the limitations of gas-liquid mass transfer, low productivities and a small product spectrum (acetate and ethanol).

This project aims to significantly improve the gas fermentation process by optimizing the conditions of continuous operation in pressurized bioreactors to improve mass transfer and productivities and expand the product spectrum to acetone/isopropanol/butanol/isoprene. More specifically, this project will be focused on Acetobacterium wieringae strain JM by: (1) studying its kinetics in comparison with close phylogenetic relatives and other relevant acetogens; (2) implementing genetic manipulation with the development of a transformation protocol, construction of functional plasmids through the screening of available genetic parts for Clostridium, and introducing heterologous biosynthetic pathways; (3) testing engineered strains in pressurized bioreactors; and (4) developing a pressurized bioreactor operating in continuous mode using the engineered strains as biocatalysts.

Based on these strategies, this PhD project will contribute significantly to the industrialization of syngas fermentation, an important sector of the biotechnology industry and to increase the knowledge on gas fermenting microorganisms.

Publication and Meetings

Arantes, A. L., Moreira, J. P., Diender, M., Parshina, S. N., Stams, A. J., Alves, M. M., ... & Sousa, D. Z. (2020). Enrichment of anaerobic syngas-converting communities and isolation of a novel carboxydotrophic Acetobacterium wieringae strain JM. Frontiers in microbiology11, 58. 

Moreira, J. P., Diender, M., Arantes, A. L., Boeren, S., Stams, A. J., Alves, M. M., ... & Sousa, D. Z. (2021). Propionate production from carbon monoxide by synthetic co-cultures of Acetobacterium wieringae spp. and propionigenic bacteria. Applied and Environmental Microbiology, AEM-02839.


VII International Conference IMFAHE - “A Global Virtual Network of European Talent to promote excellence, innovation and internationalization of Higher Education” - Oral presentation: “Converting gas to chemicals – using synthetic co-cultures of bacteria to produce propionate from carbon monoxide”

MICROBIOTEC'21 - Congress of Microbiology and Biotechnology - Poster presentation: "Development of an electrotransformation protocol for the novel acetogen Acetobacterium wieringae strain JM"



Mentee in the International Mentoring Program 2020/2021 promoted by the International Mentoring Foundation for the Advancement of Higher Education (IMFAHE/IMP)


S2M2 2021 - Summer school in metabolic modeling 2021