Periodic Reporting for period 1 - SOIL2POWER (SOIL microbial fuel cells TO (2) POWER precise irrigation systems.)
Reporting period: 2023-03-01 to 2024-02-29
Modern agriculture models tend towards promoting using resources efficiently, the sustainability of the sector, the preservation of the environment, and the safety and quality of products. Thus, water and energy access play a major role in agriculture development, being affected by their availability, as these are important determinants of land productivity. In that sense, innovative approaches towards solving these issues rely on high-precision sustainable agricultural technologies, developed to foster the demand for water and energy. Nonetheless, these are often limited by the characteristics of conventional power sources composed of heavy metals with a short lifetime that requiring manual replacement. On the other hand, greener alternatives such as solar panels, vibration energy or wind power, have proven to provide discontinuous energy supplies, while being expensive to produce, implement and maintain.
SOIL2POWERr project aims at solving this energy crisis using a new and innovative soil-microbial fuel cell (SMFC). SMFCs are power sources that take advantage of microorganisms’ metabolism, using organic matter present in the soil as fuel to generate electrical energy. The product developed, the BIOOCELL, will be a biological battery of rapid start-up, with stable high-power supply capacity, that can control irrigation valves during years without maintenance or replacement, being integrated into currently used precise water irrigation technologies producing high-impact in different areas (Figure 1).
To achieve this goal, the development of three different technology pillars are proposed: i) bioanodes containing electrogenic bacteria and redox mediators immobilized using a silk matrix for efficient electron transfer and energy production, (ii) biobattery architecture & materials optimization focusing attention on the standardization and maximum knowledge of the matrix, the soil, and (iii) low-energy consumption electronics able to control the biobattery operation at the same time that it stores the energy produced and controls the opening and closing of the irrigation valves.
SOIL2POWERr project aims at solving this energy crisis using a new and innovative soil-microbial fuel cell (SMFC). SMFCs are power sources that take advantage of microorganisms’ metabolism, using organic matter present in the soil as fuel to generate electrical energy. The product developed, the BIOOCELL, will be a biological battery of rapid start-up, with stable high-power supply capacity, that can control irrigation valves during years without maintenance or replacement, being integrated into currently used precise water irrigation technologies producing high-impact in different areas (Figure 1).
To achieve this goal, the development of three different technology pillars are proposed: i) bioanodes containing electrogenic bacteria and redox mediators immobilized using a silk matrix for efficient electron transfer and energy production, (ii) biobattery architecture & materials optimization focusing attention on the standardization and maximum knowledge of the matrix, the soil, and (iii) low-energy consumption electronics able to control the biobattery operation at the same time that it stores the energy produced and controls the opening and closing of the irrigation valves.
The goal of the project is to develop a Soil Microbial Fuel Cell (SMFC) that seamlessly integrates with existing precision water irrigation technologies, providing a continuous, clean, and reliable energy source as a maintenance-free solution. However, achieving this goal has presented significant challenges, particularly in obtaining an adequate voltage level and ensuring efficient, continuous generation of stable, autonomous power. During the first year of the project, our focus has been on analyzing the biobattery architecture and soil matrix, developing microbial bioelectrodes, and designing ultra-low-energy consumption electronics (Figure 2). The key achievements include:
Microbial Bioelectrode Development: Successful production of bioelectrodes by crystallizing silk films doped with ionic liquids and redox mediators. Bacillus subtilis, selected for its electrogenic capacity and abundance in the chosen substrate, was incorporated into the films before crystallization. A novel crystallization protocol was developed, ensuring stability and viability of the bacteria while retaining their metabolic activity after the process. The implementation of the redox mediator Prussian blue improves electron transfer, even for non-electrogenic bacteria.
Efficient Biobattery Design: Significant progress in optimizing materials and design of the biobattery reactor. Improvements in electrodes and connections have reduced production costs and operational issues. Enhanced power output was achieved through substrate selection and understanding, laying a strong foundation for a more efficient battery design.
Extra-Low Power Consumption Electronics: Determination of electronic requirements to maintain SMFCs active, along with the design of an ultra-low power consumption electronic system crucial for efficient energy management. This system enables energy harvesting from the SMFC to power the opening and closing of irrigation valves and transmit valve status via a LoRa communication module.
Microbial Bioelectrode Development: Successful production of bioelectrodes by crystallizing silk films doped with ionic liquids and redox mediators. Bacillus subtilis, selected for its electrogenic capacity and abundance in the chosen substrate, was incorporated into the films before crystallization. A novel crystallization protocol was developed, ensuring stability and viability of the bacteria while retaining their metabolic activity after the process. The implementation of the redox mediator Prussian blue improves electron transfer, even for non-electrogenic bacteria.
Efficient Biobattery Design: Significant progress in optimizing materials and design of the biobattery reactor. Improvements in electrodes and connections have reduced production costs and operational issues. Enhanced power output was achieved through substrate selection and understanding, laying a strong foundation for a more efficient battery design.
Extra-Low Power Consumption Electronics: Determination of electronic requirements to maintain SMFCs active, along with the design of an ultra-low power consumption electronic system crucial for efficient energy management. This system enables energy harvesting from the SMFC to power the opening and closing of irrigation valves and transmit valve status via a LoRa communication module.
The Soil2Power consortium aims to make a significant impact on the power-supply and agriculture industries by exceeding end-user expectations. A preliminary FTO analysis found no restrictions, and CE certification is required for EU market launch. Key Exploitable Results (KERs) have been identified, including novel crystallization protocols and advancements in electronics design. Significant progress has been made in achieving project milestones and KPIs during the first year, including bacterial immobilization on silk films.