Developing early-warning systems for improved microalgae PROduction and anaerobic DIGestIOn

Project Information

PRODIGIO

Grant agreement ID: 101007006

DOI

10.3030/101007006

Project closed

EC signature date 20 October 2020

Start date 1 January 2021

End date 30 June 2024

Funded under

• SOCIETAL CHALLENGES - Secure, clean and efficient energy

Total cost

€ 2 452 941,25

EU contribution

€ 2 452 941,25

Coordinated by

AGENCIA ESTATAL CONSEJO SUPERIOR DE INVESTIGACIONES CIENTIFICAS
Spain

Periodic Reporting for period 2 - PRODIGIO (Developing early-warning systems for improved microalgae PROduction and anaerobic DIGestIOn)

Reporting period: 2022-07-01 to 2024-06-30

Summary of the context and overall objectives of the project

Microalgae are one of nature's best examples of solar energy conversion systems, transforming carbon dioxide into biomass through photosynthesis. Microalgae biomass can be converted into methane-rich biogas through anaerobic digestion, a natural biomass degradation process carried out by bacteria and archaea in the absence of oxygen. The anaerobic digestion of microalgae biomass represents a promising biotechnological pathway leading to the establishment of a renewable fuel technology that can provide significant economic, environmental and social benefits. However, none of these bio-based production processes are yet optimized for large-scale applications, limiting their commercialization.

Bioprocess optimization depends on our ability to predict when a system becomes unstable. Ecological systems, such as microalgae photobioreactors and anaerobic reactors, are made up of tens to hundreds of microbial species that interact with each other and with the surrounding environment following non-linear dynamics. The stability of ecological systems relies on the architecture of the biological interactions network, which acts as a buffer against perturbations. As environmental conditions deteriorate and the network of interactions is disrupted, a small perturbation can lead to a sudden loss of productivity (i.e. fold-bifurcation). Catastrophe theory states that such bifurcation points tend to occur when the system approaches a tipping point. Thus, having a repertoire of early warning signals (EWS), the prelude to the system approaching a tipping point, is key to the timely implementation of corrective actions that ensure performance stability.

PRODIGIO's knowledge base will underpin the development of a system failure prediction technology, enhancing the sustainable production of biogas from microalgae. This overarching objective has been achieved by combining ‘big data’ acquisition from perturbation experiments in bioreactor systems and novel methods of computational ecology for the analysis of time-varying interaction networks. A Life Cycle Sustainability Assessment of PRODIGIO’s microalgae-to-biogas production chain has completed the work plan. The technological solutions resulting from the project, such as a catalogue of EWS for the failure of microalgae biomass production and anaerobic digestion processes, are pre-commercial (Technology Readiness Level 3-4). However, we have identified priority research lines for further development and future implementation of this technology. If successful, the results of PRODIGIO will pave the way for moving the entire microalgae-to-biogas production chain efficiently towards its theoretical maximum, enabling the development of a truly sustainable microalgae-derived biogas production industry.

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

PRODIGIO comprised two lines of research, each focused on analyzing the bio-based production systems explored in the project: microalgae photobioreactors (PBRs) for biomass production (Work Packages 1 and 3) and anaerobic reactors (ARs) for biogas conversion (Work Packages 2 and 4). Each line involved experimental (Work Packages 1 and 2) and analytical (Work Packages 3, 4, and 5) stages. The experimental stage consisted in sampling and data collection, while the analytical stage employed big data analysis using (meta)genomics and chemical fingerprinting, alongside empirical dynamic modeling for time series analysis (Work Packages 3 and 4). A Life Cycle Sustainability Assessment of PRODIGIO's microalgae-to-biogas chain (Work Package 5) has been carried out to evaluate the actual potential of the technology proposed.

All samples and data, from both microalgal PBRs and bench-scale ARs, were analyzed using standard methods, including routine variables, metabarcoding, metagenomics, metaproteomics, and high-resolution mass spectrometry. This created a comprehensive database, invaluable for investigating bioreactor community responses to perturbations. Applying bioinformatics (Work Packages 1, 2, 3, 4) and empirical dynamic modeling (Work Packages 3, 4) revealed ecological complexities under normal, stressed, and failure conditions. This included reconstructing potential chemical-microbial interactions within bioreactor interactomes and analyzing network properties to uncover key architectural and dynamic features.

Key project results include: i) comprehensive descriptions of algal microbiome structure, diversity, and dynamics; ii) detailed descriptions of biochemical and ecological responses of microbial communities to common AR shocks; iii) reconstruction of PBR and AR interactomes; iv) the discovery of stabilizing positive and negative microalgae-microbiome interactions; v) identification of cascading transitions in key species and metabolites preceding methanogenic ecosystem collapse; and vi) a comprehensive assessment of environmental, social, and techno-economic aspects of PRODIGIO's biogas production chain, pinpointing areas for improvement and implementing sustainable practices to maximize the efficiency of processes and minimize the environmental footprint.

Ultimately, PRODIGIO's findings provide an empirical basis for developing effective early warning signals (EWS) for system failure in microalgae production and biomass to biogas conversion systems. Specifically, key population dynamics and chemical compounds were identified as potential EWS, enabling proactive interventions to prevent bioreactor collapse and enhance operational stability beyond current capabilities.

Overall, this research not only advances scientific knowledge but also has practical implications for enhancing the reliability and sustainability of microalgae biomass and biogas production systems. The potential for publication in high-impact scientific journals underscores the significance and relevance of these findings to the scientific community and stakeholders in the microalgae and renewable energy sectors.

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)

PRODIGIO's in-depth ecogenomic analysis of bioreactor systems has yielded invaluable insights into the complex interactions between microorganisms and their environment. The project's meticulous study of interactomes, that is, the intricate networks of ecological relationships within bioreactors, has revealed crucial triggers for system failures. This knowledge will be instrumental in developing early warning signals, empowering operators to proactively manage and optimize bioreactor performance, thereby preventing costly disruptions and maximizing productivity.

Furthermore, PRODIGIO's comprehensive life cycle assessment (LCA) has provided a rigorous evaluation of the environmental and economic sustainability of this emerging technology. The LCA underscores the potential for substantial reductions in both the cost and environmental footprint of microalgae biomass production and its conversion into biogas. This is a critical step towards making microalgae-based biofuels a commercially viable and environmentally responsible alternative to conventional fossil fuels.

The cumulative impact of PRODIGIO's research and development efforts is expected to significantly accelerate the commercialization of microalgae biomass and biogas production in the coming years. This technology not only aligns with global sustainability goals but also opens up new economic opportunities in the burgeoning bioenergy sector.

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