The primary goal of this project is to enhance the electroactivity of marine bacteria, including Desulfuromonas acetoxidans, through bioengineering, to advance their practical application in water desalination processes. The modified strains will first be tested in a lab-scale Microbial Desalination Cell (MDC), followed by scale-up experiments to assess their growth and EET performance under real-world conditions.

The key methodology is the genetic manipulation of Desulfuromonas acetoxidans using established tools for Geobacter sp., which belongs to the same genus. Genes identified as key players in EET processes will be either deleted or overexpressed to enhance the efficiency of electron transfer to electrodes. If necessary, other genes may be introduced into the marine organism to facilitate biofilm formation or improve electron exchange with electrodes. The performance of the engineered variants will be assessed by evaluating their capacity to form biofilms, growth in bioelectrochemical systems (e.g., microbial fuel cells and MDC), and EET efficiency across media with varying salinity levels. Additionally, a methodical approach to the initial digital transformation will be put into place to establish the foundations for the digitalisation and optimisation of MDC technology for useful and expandable applications.

The hypothesis being tested is that genetic engineering can improve EET capabilities and adaptability of marine bacterial strains under conditions relevant to water desalination. This project uses an approach aimed at determining whether targeted modifications can create strains suitable for practical bioelectrochemical applications in saline conditions. Additionally, the scale-up process of MDC will be tested with the integration of real-time digital monitoring tools to evaluate the strain’s performance and identify the main challenges in expanding the system.

Our system will work with pure cultures of native and modified strains of Desulfuromonas acetoxidans. In parallel, other marine species that are facultative anaerobes and thus more manageable under laboratory conditions can also be investigated.

One of the major outcomes is to construct an engineered strain that outcompetes its native strain in water desalination. This will be crucial for advancing the project and upscaling MDC. It will also provide valuable insights into the processes that enhance EET, enabling the manipulation of other marine electroactive bacteria for practical application in bioelectrochemical systems, including desalination and bioenergy generation using saline wastewaters. If successful, another major outcome will be the digitalisation of the MDC process, crucial for identifying the major challenges to the practical application of these systems and for developing effective strategies to overcome them.

One of the main challenges in this project is to develop a quick and effective protocol to genetically manipulate Desulfuromonas acetoxidans. Another significant risk is the insufficient data available for digital monitoring and analysis of system parameters, critical for the successful scale-up and optimisation of MDC technology.

This project will be performed in collaboration with Sebastià Puig (University of Girona) and Abraham Esteve-Núñez (Universidad de Alcalá de Henares), who will also act as supervisors. Two secondments are predicted for DC6: at the University of Girona to optimize the growth of the bacteria (native and genetically manipulated) in a MDC, followed by a step-by-step process toward the first digital transformation, and at the Universidad de Alcalá de Henares, with the help of METFilter, to improve and scale-up the MDC process and evaluate the growth and EET ability of the native and modified strain of Desulfuromonas acetoxidans under real conditions.