About 8-9% of fossil fuels consumed in the EU are used as raw material in various industrial processes. About half of this amount is used in the manufacture of polymers. Fossilised carbon is therefore transformed into products that may, at the end of their useful life, release this carbon into the atmosphere, contributing to climate change. As an alternative or complement to petroleum-based polymers, a series of biopolymers or bioplastics have been developed from natural sources (e.g. wheat, corn and sugarcane); these have environmental benefits, through reduced greenhouse gas emissions and lower energy consumption, economic benefits as alternatives to expensive petroleum products, and reduce reliance on fossil fuels. The European bakery sector produces 3.5 million tonnes of retrodegradated starch waste with minimal nutritional value every year. At least 5% of this waste is disposed of in landfill because there is currently no alternative use.
The main objective of the BREAD4PLA project was to demonstrate the technical and economic viability of using waste products from the bakery sector in the fabrication of a 100% biodegradable plastic film. The project aimed to establish and operate a pilot plant at pre-industrial scale for the synthesis of poly-lactic acid (PLA) from bakery waste products, using a low-energy process with water-based enzymes. The project also aimed to demonstrate practical uses for this PLA as a thermoplastic packaging film that meets current requirements and standards.
The BREAD4PLA project proved that bakery waste is a suitable raw material for compostable plastic packaging. This was done through an analysis of all stages, from the selection and characterisation of bakery waste, enzymatic fermentation, PLA polymerisation and plastics processing pathways, including the use of additives such as thermal stabilisers to avoid PLA molecular degradation, and the production of sheets of packaging material. The project demonstrated this at the pilot-plant scale. Each stage is crucial for the next, so constant feedback between the four specialist partners (AIMPLAS, ATB, University of Bangor and CETECE) was crucial for the project’s success.
From the technical point of view, the main achievement was the demonstration of the packaging production process, followed by its validation using different types of bakery and pastry waste as raw material. The main innovation was the demonstration of the use of bakery waste as a novel raw material to produce PLA packaging, and showing that the product had the same performance as PLA packaging produced from cereals - while also addressing the problem of food waste disposal. Validation tests with different bakery products showed that the packaging developed from bakery waste has a good performance for use within the bakery sector.
Replicability can be considered viable as this type of waste is available in all European countries, and the project’s result suggest that a scale-up to industrial level would succeed with the corresponding optimisation in terms of cost reductions. Specifically, Germany and the UK generate the largest amounts of this type of waste in Europe, which makes them candidate countries for initiating the project results at industrial scale. The main constraint on industrial transferability is the investments required to create the corresponding lactic acid/PLA production plants in Europe, which are currently lacking. However, the economic analysis performed in the project demonstrated the potential viability of medium-scale production plants that used industrial waste generated by nearby baking companies. This would require the collection of large amounts of bakery waste from different producers to assure a constant supply, so preservation and transport costs, as well as a guarantee of homogeneous raw material, need to be considered. The project defined a protocol for the preservation of waste, from collection, through transport, to lactic acid production plant.
The project partners found that companies generating different types of food waste (e.g. fruit and vegetables) would also be interested in collaborating to use their waste to produce biodegradable packaging material. Adaptations on the final thickness of the packaging would be necessary to transfer the technology to other sectors, to preserve products during their required shelf-life. The potential of the new packaging, and consequently the use of food waste for their production, is therefore high. As a result of project dissemination activities, interest has been expressed by companies in a number of European regions.
The BREAD4PLA process for “cradle-to-cradle” management brings direct environmental benefits by effectively closing the loop for industrial bakery waste. The waste is recovered using a clean enzymatic biotechnology to polymerise the PLA material; with a yield level of 48%, which is expected to increase at a large scale. The amount of waste that can potentially be diverted away from landfill via BREAD4PLA technology is about 4 000 tonnes per year from each large bakery company. This also adds value to industrial bakery waste, since it is instead used to produce bioplastic packaging material. Based on pilot plant process yields, the recovery of the waste generated in a large bakery company can lead to the production of 680 tonnes of PLA per year, replacing the equivalent amount of fossil fuel-based plastics from non-renewable sources. The PLA from bakery waste can therefore be totally recycled or composted, while the small amount of PLA scrap arising can be reintroduced into the production process. The project outcomes help to implement the Waste Framework Directive (WFD) and other European Directives and legislation relating to waste and recycling. Long-term socio-economic benefits include local job creation, for example, through bakery waste collection and new PLA production plants.
Further information on the project can be found in the project's layman report and After-LIFE Communication Plan (see "Read more" section).