Since the beginning of the M4BG project, a major focus has been on demystifying the complex processes within biogas production, often referred to as a “black box” due to the limited understanding of what occurs inside a biodigester. Gaining deeper insights into these processes requires a thorough understanding of the microorganisms involved and identifying which ones optimize performance.

The goal is to uncover the microbial mechanisms involved in biogas production and improve key factors such as yield (the amount of biogas), quality (methane percentage), speed (time to achieve production), and the robustness and replicability of the process.

We asked Manel Porcar, M4BG coordinator from the University of Valencia (Spain), about advancements in understanding how microbes operate in the process. According to him, “It’s crucial to establish a specific microbial profile, encompassing a diversity of microorganisms. This includes not only archaea, responsible for methane production but also bacteria engaged in various metabolic pathways that support archaea in biogas production.”

Thanks to the hard work of Darwin Bioprospecting, Manel’s company, along with Bioclear Earth and The Technische Universität Dresden—also part of the M4BG project—have discovered a new taxonomic order of bacteria: Darwinibacteriales, or, as known by its scientific nomenclature, MBA03. These bacteria collaborate with archaea in the generation of methane.

Listen to our last online panel discussion on Fuelled By Microbes, where experts Manel Porcar, Adriel Latorre and Pascal Otto spoke about this discovery and the fascinating world of microbiology research!

The next step was confirming that these new microorganisms enhanced biogas plants’ performance. And —spoiler alert—, they succeeded. “We use digestate, the solid residue from anaerobic digestion in biogas production, sourced from the Netherlands and enriched with these Darwinibacteriales. We have inoculated this into the biogas plants in Aras de los Olmos,” Manel tells us.

Aras de los Olmos is a small town in Valencia where Manel and his team will put this enriched digestate to the test and monitor its success. There are two small bioreactors, each with a capacity of about 3 cubic meters, which is smaller than industrial-scale bioreactors (usually starting at 200 cubic meters).

Though they might be small, they are very practical as they are identical twins. “This setup has allowed us to have a control reactor, which operates normally with biomass consisting of a mixture of pig and rabbit manure, and a test reactor, which contains the same manure mixture but is also inoculated with a small percentage of that Dutch digestate enriched with these bacteria that we believe are essential,” Manel explains.

Samples are being taken to carry out two types of analyses: one microbiological, to see if the Darwinibacteriales indeed colonize the biomass and produce more biogas, and another to measure various parameters that, as Manel notes are “related to the efficient functioning of the biogas.“

So far, the results are very promising, and we expect to see amazing outcomes soon. The goal is to achieve “a unique view of a digestate transplant experiment,” something that hasn’t been done before. “This will allow us to see how useful it is to use a high-quality digestate with a perfectly characterized microbial profile to improve biogas production,” concludes Manel.

Stay tuned to witness the results of our experiment in Aras de los Olmos!