Phytoplankton Towards Valorization of Ammonia-containing Liquid for Upgraded Economy

Project Information

PhyToVALUE

Grant agreement ID: 101067916

DOI

10.3030/101067916

Project closed

EC signature date 29 July 2022

Start date 17 July 2023

End date 16 August 2025

Funded under

• Marie Skłodowska-Curie Actions (MSCA)

Total cost

No data

EU contribution

€ 181 152,96

Coordinated by

UNIVERSIDAD DE VALLADOLID
Spain

Periodic Reporting for period 1 - PhyToVALUE (Phytoplankton Towards Valorization of Ammonia-containing Liquid for Upgraded Economy)

Reporting period: 2023-07-17 to 2025-08-16

Summary of the context and overall objectives of the project

Ammonia (NH₃) is a key compound in agriculture and wastewater treatment. It is both an essential nutrient and a potential pollutant: in excess, it is toxic to aquatic organisms and can destabilize algal cultivation systems. In Europe, where resource efficiency and circular economy are strategic priorities, the valorisation of waste-derived nutrients such as NH₃ is of increasing importance. At the same time, reliable and affordable tools for monitoring NH₃ toxicity in real time are lacking.

The PhyToVALUE project set out to address this challenge by developing a fluorescence-based method and device to detect NH₃ toxicity in microalgae rapidly, non-destructively, and at a low cost. Its overall objectives were:
-To evaluate different fluorescence methods and identify the most sensitive approach for detecting NH₃ inhibition.
-To establish a statistical model to distinguish NH₃ toxicity from other environmental stressors.
-To develop a low-cost and open-source monitoring device.
-To test the system in longer-term cultivation experiments with the aim of integrating it into ammonia feeding control.

By pursuing these objectives, the project contributes to the European Green Deal goals, providing tools that support sustainable resource use, reduce reliance on synthetic fertilizers, and enhance algal biotechnology.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

Over two years, PhyToVALUE conducted experiments with three representative algal species (Chlorella vulgaris, Acutodesmus obliquus, Arthrospira platensis).

- Screening of methods: Among several fluorescence approaches, the OJIP transient was identified as the most sensitive. A novel diagnostic signal, the K peak, was discovered, specific to NH₃ stress.

- Recovery and discrimination: Cultures could recover from NH₃ exposures up to ~150% of the inhibitory concentration (EC₅₀). A Lasso regression model was developed to discriminate NH₃ stress from other stressors (light, heat, metals), achieving reliable predictions even under complex conditions.

- Device development: A low-cost, open-source fluorometer (MultiJIP) was built, with dual-wavelength LEDs, variable excitation intensity, and a graphical interface. The system enables real-time estimation of NH₃ toxicity and will be released openly via GitHub.

- Application to cultivation: The method was validated in fed-batch cultures under simulated diurnal light cycles, confirming feasibility under realistic dynamic conditions. While full closed-loop control was not implemented, the monitoring framework was proven.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

The project delivered several advances beyond the original state of the art:

- Novel diagnostic marker: The OJIP K peak was established as a specific indicator of NH₃-induced damage to the photosynthetic machinery, offering unprecedented sensitivity compared to traditional parameters such as Fv/Fm.

- Seconds-scale detection: NH₃ toxicity can now be detected in seconds, without destructive sampling or lengthy chemical analysis.

- Quantitative recovery thresholds: The project defined species-specific recovery capacities (~150% EC₅₀), providing new insights into reversible vs irreversible stress.

- Affordable monitoring technology: The MultiJIP device provides high-quality data at a fraction of the cost of commercial fluorometers, supporting broader adoption and reproducibility.

- Open science commitment: All tools (hardware designs, software, datasets) will be released openly, ensuring transparency and enabling replication across laboratories worldwide.