Background Ecosystems are becoming degraded as a result of the exhaustive use of non-renewable resources such as petrochemical-based polymers. The environmental impact of long-lasting plastic waste is a growing global concern. Solutions such as incineration produce significant greenhouse gas emissions. Petrol-based plastics are mostly used in packaging (food and non-food applications) as a low-cost product that is generally not reusable or not foreseen for reuse. These materials have a major environmental impact because of their non-biodegradability. Europe produces 67 millions tonnes of plastic waste per year, with a high carbon footprint (167-203 billions tonnes of CO2 equivalent). Nearly 50% on average of all petrol-based plastic in the EU, most of it packaging, goes to landfill. The food-packaging market remains dominated by petrol-based plastic (99% market share), but there is a growing market for bio-based plastic produced from renewable resources. The global production of bioplastic could reach 5.8 million tonnes in 2016, up from 1.2 million tonnes in 2011. One by-product of the agri-food industry that could be used in packaging production is whey from cheese making (around 9 tonnes of whey per tonne of cheese). Whey is mostly water (around 85% weight/volume) and contains the solids present in whole milk, including whey proteins (20% of total proteins), and most of the lactose, water soluble vitamins and minerals. EU27 whey production is about 50 million tonnes. At present, most is used to produce whey powder, which is used as a dietary supplement, but the quantities of whey produced surpass by far the demand for whey powder. Objectives The LIFE+ WHEYPACK project will demonstrate the environmental and socio-economic benefits of producing a biodegradable food packaging material using polyhydroxybutyrate (PHB), which is obtained from whey; PHB will be produced using a process of microbial fermentation. In particular, the project will: Demonstrate the environmental, technical and economic feasibility of: o PHB bioproduction from whey; o Polymer compounding; and o Development of partly biodegradable PHB-based packages (trays) and demonstration of their application to dairy products: cheese packaging; Demonstrate that total greenhouse gas emissions from the new production process are lower than from manufacturing of petrol-based food packages (polypropylene, PP). Energy and water consumption will also be assessed; Study the conditions for scaling up of the process from pilot to industrial scale. Expected results: A PHB-based packaging manufacturing process (using whey) that has a carbon footprint 35% lower than PP-based packaging manufacturing; A 75% reduction in BOD (biological oxygen demand) and a 40% reduction in COD (chemical oxygen demand) of the ‘industrialised’ whey by-product (after its use for PHB production) when compared with original whey by-product without treatment; Reduction in the production cost of PHB polymer of up to 50% because of the use of dairy by-products (revalorisation of whey surplus), instead of purpose-grown crops as raw materials; Production of 100% biodegradable packages (200 pilot units) based on PHB polymer obtained by injection moulding processes (trays), which will be used for dairy products (cheese).