Bioplastics from Waste
Bioplastics from Waste streams Martin Markotsis with the biospife The biospife with Zespri kiwifruit Bioplastic products from kiwi waste New Zealand has extensive forestry, agricultural and horticultural industries that produce significant volumes of biomass waste. Scion, New Zealand’s forestry research institute, is discovering and developing new ways to use biomass that add value and reduce waste. Scion’s research includes the transformation of biomass wastes into novel additives and improved biopolymers, adhesives, coatings or composites to create a range of added-value waste-derived industrial products. These all contain various types and amounts of processed and modified biomass waste streams and can be processed by extrusion, injection moulding, or thermoforming. Two of the recent research successes are ‘Waste 2 Gold’ and the Zespri ® biospife. ‘Waste 2 Gold’ is a major research programme with the goal of converting biomass waste into valuable products. Scion has recently developed exciting new technology that converts solid waste from municipal sewerage treatment plants into useful industrial feedstock chemicals. This technology, called TERAX, is a hydrothermal oxidation process and has generated lots of interest from local authorities. The Rotorua District Council was so impressed that it has partnered with Scion to build and operate a pilotplant scale facility at its municipal wastewater treatment plant, which deals with waste from the 60,000 inhabitants of this New Zealand city. Industrial waste water (such as pulp and paper mill effluent) can be used as growth environments for special bacteria that not only produce bioplastics but also remediate the water. Details of some of Scion’s other biomass-based bioplastic developments can be found in previous issues of bioplastics MAGAZINE [1,2]. Another successful collaboration is with Zespri, the company that markets New Zealand kiwifruit worldwide. A survey, commissioned by Zespri, identified approximately 50,000 tonnes per year of waste biomass from the New Zealand kiwifruit industry. Sustainability is an important driver for Zespri who decided to partner with Scion to investigate environmentally friendly products and processes for utilising these residues in plastic products within Zespri’s value chain. Kiwifruit waste comes either from whole fruit unsuitable for fresh sales or export or residues from fruit processing operations, such as juicing. A key issue with kiwifruit waste is its high moisture content. Scion has developed new technology that transforms these residues into a plastically processable intermediate, which can then be blended or formulated with other bioplastics/plastics. This next step was to use this fruit-waste bioplastic instead of oil-based plastic. The spife was chosen because it is a unique combined spoon-knife utensil designed for cutting, scooping and eating kiwifruit. Currently, spifes are made from polystyrene which Zespri has found contributes 3% to the company’s total carbon footprint. Scion and Zespri are working together to develop a novel biospife to retail with kiwifruit. A bioplastic formulation has been optimised to generate a material that can be processed on existing injection-moulding equipment as well as having mechanical properties similar to, or better than, the current general purpose polystyrene. Scion’s life cycle analysis (LCA) team studied the biospife production and found the real environmental advantage of the kiwifruit bioplastic came with composting at the end of life. 20 bioplastics MAGAZINE [04/12] Vol. 7
Bioplastics from Waste streams Thermoformed trays made from kiwifruit bioplastic/PLA formulation Composting trial of the biospife By Alan Fernyhough and Martin Markotsis Biopolymers and Chemicals, Scion Rotorua, New Zealand So, the vision for the biospife is a bioplastic utensil that can be placed into an industrial composting waste stream, along with the kiwifruit skins, once the consumer has finished eating. This would remove the need for people to sort the biospife and kiwifruit waste into different recycling bins. Zespri in Europe had such a positive response to prototype biospifes, displayed at the BioVak trade fair for sustainable agriculture in The Netherlands, that commercial scale biospife production trials are now underway. The biospife is both renewable, being formulated from plant materials such as kiwifruit and corn, and compostable under industrial composting conditions. Scion is currently measuring the composting profile of the biospife using their in-house biodegradation test facility. Developing a bioplastic from kiwifruit residues is a winwin for everyone; excess fruit material is diverted from waste streams and converted to a higher value product, the carbon footprint for Zespri is reduced, and there are clear marketing benefits. With the successful development of kiwifruit bioplastic formulations for the biospife, Scion’s biopolymers and chemicals team have begun to investigate other possible kiwifruit bioplastic products in Zespri’s value chain such as packaging materials. Scion and Zespri had been working with another company, Alto, to mould the biospifes. These three companies also worked together to trial a similar fruit bioplastic/PLA formulation in the thermoformed trays used in packaging and displaying the kiwifruit. This success demonstrates Scion’s ability to add value throughout the logistics and supply chain for commercialscale biospife production from supply of fruit, bioplastic formulation and compounding, through to injection moulding. Scion is also working with other companies, such as LignoTech Technologies, who have developed technology to transform corn ethanol waste biomass (DDGS) into a costeffective, low density, bio-based filler material for plastic composites which they are looking to commercialise in the USA. www.scionresearch.com www.zespri.com REFERENCES: [1] Fernyhough, A. From Waste 2 Gold: Making bioplastic products from biomass waste streams, bioplastics MAGAZINE, 2 (4), 2007. [2] Fernyhough, A. Bioplastic Products from Biomass Waste Streams, bioplastics MAGAZINE, 3 (5), 2008. http://www.youtube.com/watch?v=Ji1B-RQuDk0 bioplastics MAGAZINE [04/12] Vol. 7 21
