Unlocking microbial secrets that transform biogas production
Biogas is a storable and renewable energy source, but its production through anaerobic digestion is not yet fully understood. The transformations that happen during the process carried out by microorganisms are still referred to by scientists and engineers as a ‘black box’. The EU-funded MICRO4BIOGAS(opens in new window) project set out to illuminate this biological mystery, aiming to optimise the biogas production process. “MICRO4BIOGAS focused on improving the process in two main ways,” says Manuel Porcar, MICRO4BIOGAS project coordinator and researcher at the University of Valencia. The research deepened the microbiological understanding of anaerobic digestion through advanced analysis techniques and selected “key microorganisms involved in the process that can enhance the stability, robustness and yield of biogas production.”
Unveiling microbial secrets
MICRO4BIOGAS achieved exceptional results in both of its approaches. One of the project’s most significant achievement was the discovery of a core microbial community common to most anaerobic digesters worldwide. “Darwinibacteriales is a new taxonomic order that has been described in this project and which seems to improve methane production thanks to its interaction with methanogenic archaea(opens in new window),” explains Porcar. The research team successfully isolated microbial strains that demonstrated measurable improvements in biogas production. Laboratory and pre-industrial scale trials showed that several strains could enhance biogas production by more than 15 %, with some cases also resulting in gas quality improvement due to higher methane content. Impressively, experiments indicated that transplanting selected digestates, the nutrient-rich material remaining after anaerobic digestion, could boost biogas production by 30 % while reducing production start-up times. These tests were conducted at the pilot biogas plant in Aras de los Olmos, a town in Spain that aims to self-supply all its energy through renewable means.
Developing practical bioaugmentation solutions
The project’s approach focused on bioaugmentation(opens in new window) – introducing beneficial microorganisms to improve biological processes. While this technique is applied in many fields of science, its application to biogas production has been limited due to insufficient understanding of anaerobic digestion(opens in new window) and the lack of efficient, scientifically validated microbial additives. MICRO4BIOGAS demonstrated that cultivated microbial strains and microbiome transplantation could serve as effective bioaugmentation strategies. The latter is particularly valuable when organisms cannot be cultivated in laboratory conditions, like the Darwinibacteriales. Looking towards practical implementation, the project envisions the development of bioaugmentation kits in two forms: powder-like products containing beneficial bacteria and archaea(opens in new window) or selected digestates enriched with specific microbial consortia. “Plant operators would simply need to add the product to the reactor and wait for biogas production to improve,” says Porcar. While further testing is needed before market-ready products emerge, MICRO4BIOGAS has laid crucial groundwork for developing new microbial solutions. “Anaerobic digestion is a highly variable process and is carried out differently depending on the biogas operator. We need to determine whether our strains and microbial communities can support all processes or only improve specific ones,” notes Porcar. “Additionally, non-scientific factors – such as the economic viability of microbial additives for producers or the regulatory framework for marketing them in each country – still need to be addressed. That said, we are much closer to real-world application than we were four years ago.” By cracking the anaerobic digestion ‘black box’, MICRO4BIOGAS sets the stage for bioaugmentation products that could transform biogas plants worldwide into efficient, predictable renewable energy producers – advances that are just beginning to unfold.
