A new study, published in Scientific Reports and carried out by Brazilian researchers in collaboration with German and Swedish institutions, reveals that agro-industrial waste, such as beer grounds and banana leaves, can be used to grow mushrooms and make sustainable biocomposites.
Conducted in the Santa Catarina region, Brazil, This research demonstrates how these wastes, when properly combined, optimize mushroom production and generate biodegradable materials. The results indicate an important step towards a circular economy, where waste is transformed into valuable resources, reducing dependence on plastics and promoting sustainable practices.
Beer waste, a sustainable resource
Beer production generates large quantities of pomace, a by-product that is rich in nutrients but typically disposed of inappropriately, impacting the environment. In this study, researchers used this pomace, fresh and dried, mixed with banana and pupunha leaves, as a substrate to cultivate the Pleurotus sajor-caju mushroom. By mixing the pomace with the leaves, it was possible to increase the productivity of the crop, indicating that the use of local waste offers a viable and ecological alternative to the disposal of waste in nature.
In addition to allowing more efficient growth of mushrooms, these mixtures have proven to be a source of nutrients, without the presence of toxic elements such as lead or mercury. Thus, this innovative use of bagasse responds to a circular economy model, where the waste of one industry becomes the raw materials of another.
Nutritious and sustainable mushrooms
Mushrooms grown in the pomace and leaf substrate were found to be high in protein, phosphorus and other nutrients, and low in sodium, making it a nutritious food with beneficial properties for health.
These mushrooms contain all the essential amino acids, as well as a good proportion of unsaturated fatty acids and minimal fat content.
As they are grown on natural waste, these mushrooms have a lower production cost and can meet the growing demand for sustainable food. Furthermore, The Pleurotus sajor-caju is one of the most popular types of edible mushrooms in Brazil and around the world, due to its nutritional value and ease of cultivation in a variety of substrates.
Production of sustainable biocomposites
After harvesting the mushrooms, The leftover substrate is used to produce biocomposites, materials similar to moss and wood that can replace plastics. These composites exhibit satisfactory mechanical properties, such as high compressive strength and low moisture absorption, making them suitable for packaging and lightweight construction.
Biocomposites made with residual substrate showed greater strength and density than those made with fresh substrate, thanks to the development of mycelium in the mushroom residue. These materials are biodegradable and, at the end of their useful life, return to the soil, helping to reduce the use of synthetic materials and promoting sustainability.
Benefits and future prospects
This study highlights the advantages of exploiting agro-industrial waste, contributing to the reduction of environmental impacts and the valorization of local materials. The reuse of beer grounds in a sequential production system of mushrooms and biocomposites opens the way to new sustainable solutions, saving natural resources and reducing waste.
Future research could expand these applications by exploring the impact resistance, thermal conductivity, and sound absorption of biocomposites. Furthermore, the antimicrobial potential of the fungus can be evaluated to develop smart packaging. The study therefore offers an innovative and ecological vision of waste, beneficial for the environment and encouraging more responsible industrial practices.
Article reference:
do Nascimento Deschamps, JL, Schulz, JG, Riani, JC et al. Sustainable production of Pleurotus sajor-caju mushrooms and biocomposites using brewer’s spent and agro-industrial residues. Sci Rep 1426281 (2024).
