Ectoines, including ectoine and hydroxyectoine, are cyclic amino acids synthesised intracellularly by microorganisms to protect themselves from radiation, salt and heat stress and dehydration. Since these compounds stabilise DNA, lipids, proteins, cells and other macromolecules, they have applications in medical, cosmetic and pharmaceutical industries, including skin protection and respiratory problems [1] (Becker and Wittmann, 2020). Furthermore, their high market prices of 600 to 1000 €·kg^-1 made them an up-and-coming industry [2] (Pérez et al., 2023).

Methanotrophic organisms and ectoine

Several methanotrophic microorganisms are ectoine producers in saline environments [3] (Gęsicka et al., 2021). These methanotrophic microorganisms are characterised by using methane as a carbon and energy source for their growth and production of metabolites. Methanotrophic microorganisms release ectoine when exposed to environments without salinity, as ectoine are not necessary anymore for protection against salt stress. However, if exposed again to a saline environment, these microorganisms will accumulate ectoines again. This sequence of hypo- and hyperosmotic shocks is known as biomilking and is used in the secretion of ectoines. Biomilking allows the release of ectoines to a water medium for further downstream purification and application as raw ingredients in cosmetic and medical industries [1] (Becker and Wittmann, 2020).

Methanotrophic organisms can be cultivated in biogas, which contains methane that can be biotransformed into ectoines. In this sense, ectoines produced from the methanization of biowastes exhibits a remarkable market opportunity in the cosmetic industry. Indeed, the cosmetic industry has been increasing its commitment with zero waste and a circular economy during recent years. Green ingredients such as bacterial ectoines are a powerful strategy to improve this industry’s sustainability.

Ectoine at CHEERS project

Based on its research experience on lab-scale production of ectoines [4] (e.g Herrero-Lobo et al., 2024), the Institute of Sustainable Processes of the University of Valladolid has a leading role in the ectoines´ valorisation line of the CHEERS project. Thanks to the effort of the involved partners (ISP-UVa, MAHOU-SAN MIGUEL, SYSPRO, AQUALIA and GENIA), during the next months, a biofermentor for methane bioconversion into ectoines and the units for biomilking and downstream processing of ectoines will be installed in the demo-site, allowing to assess the process at a real scale. In this sense, the CHEERS project is revealing the beauty of wastes, promoting a higher circularity in the cosmetic and brewery industries by taking the production of ectoines from the methanization of biowastes to a next step in the consolidation of the production and downstream processing technologies.