CHEERS is a European project that seeks to give a new value to the underutilised or residual secondary flows generated during the brewing process, converting them into five highly valuable and competitive bio-based products in the market. In this sense CHEERS is based on a biorefinery model, which offers 5 novel biotechnological routes that, in turn, generate 5 bioproducts: transformation of bagasse into insect protein drink, conversion of CO2 and wastewater from the brewing process into caproic acid for animal feed, conversion of CO2 into chlorine for sanitising products and conversion of biogas into ectoin for cosmetic products and into microbial protein for pet food production.
All CHEERS value chains are based on innovative bioprocesses and biofermentors that ensure sustainable transformation processes, which will be validated on a demonstration scale in an industrial brewery of the company Mahou San Miguel. In an initial phase of the project, the possible implementation of these technologies in three other bio-industries has also been studied in order to demonstrate their potential beyond the brewing industry: wastewater treatment plants, waste treatment plants and the wine industry.
To assess the applicability of these technologies in these industries, a detailed analysis of the composition and mass flows of solid waste (biomass), wastewater and greenhouse gases was carried out. More specifically, the nutrients present in the biomass, such as nitrogen and phosphorus, as well as the amounts of methane (CH4) and carbon dioxide (CO2) available and needed to support microbial growth in the biotechnologies used in CHEERS were examined. All these data were compared with the brewing industry as a reference.
The results revealed that the waste from the wine industry contains considerably high amounts of nutrients (nitrogen and phosphorus), which can be used for the bioconversion processes of the project. In addition, a much higher amount of methane was discovered in the waste treatment plants than in the brewery, which could be used for the production of ectoin. On the other hand, although the amounts of carbon dioxide (CO2) available for the production of chlorine or volatile fatty acids were lower in these three industries than in the brewery, their possible use is not ruled out.
In summary, the comprehensive mapping of emissions and effluents in bio-industries has shown that it is feasible to use part of their waste streams (gas and liquid phase) as feedstock for the production of high value-added bio-based compounds using the biotechnologies of the CHEERS project. In general, the availability of nutrients to support the growth of methanotrophic or volatile fatty acid producing biomass will be limited compared to the availability of CO2 or CH4 available in breweries and wineries. In this scenario, an external nutrient source could be used for conversion of the available carbon. In waste and wastewater treatment plants, nutrient availability is aligned with carbon availability, so CHEERS technologies for the production of ectoin, microbial protein, caproic acid or chlorine could be implemented without the need for external nutrient sources.