BioTWINE hop waste transformation into novel product assortments for packaging and horticulture sector; LIFE18 ENV/SI/000056 | Acronym: LIFE BioTHOP

The harvesting of hops generates a substantial amount of residual biomass (15 tons from each harvested hectare). During hop harvest, the entire above-ground plant mass is removed from the field. After the cones are separated, the remaining biomass, consisting mainly of leaves and bines, is left beside the harvesting facilities. This material represents a potentially valuable source of organic matter and nutrients that could be returned to agricultural land. However, its further use is significantly limited by the presence of synthetic polypropylene (PP) twine, which is used to support hop plants during growth. Because the twine remains tightly entangled in the residual biomass, the material becomes mixed waste, preventing its effective reuse and creating an environmental burden. The main objective of the project was to replace conventional PP twine in hop fields with biodegradable twine made from the renewable material polylactic acid (PLA). Unlike PP twine, PLA twine can be degraded through on-farm composting together with hop plant residual biomass into simple decomposition products, including water, carbon dioxide, and organic matter. The project developed clear guidelines for the proper composting of hop biomass waste, ensuring that the process results in a high-quality organic fertilizer with the potential to match or even exceed the quality of farmyard manure. This approach makes it possible to produce high-quality organic fertilizer within approximately seven months, which can then be reused on the farm. In this way, nutrient cycling is effectively closed within the agricultural system. In addition, the project demonstrated the production of more than ten biodegradable products derived from hop plant residual biomass, including planting pots, bottle packaging, biocomposites, paper, and construction or play bricks. All of these products are fully biodegradable and compostable, allowing nutrients to be returned to agricultural land after the end of their useful life, thereby extending the circular use of biomass beyond the farm itself. Overall, the project showed that hop agro-waste can be reduced dramatically, potentially by up to 100%, while establishing a circular economy model within hop production systems.