Materials Waste cooking
Materials Waste cooking oil makes bioplastics cheaper Waste cooking oil Bacterial fermentation PHA within bacterial cells Isolated bioplastic! Bioplastics that are naturally synthesized by microbes could be made commercially viable by using waste cooking oil as a starting material. This would reduce environmental contamination and also give high-quality plastics suitable for many applications, according to scientists who presented their work at the Society for General Microbiology‘s Autumn Conference (03 - 05 Sept. 2012) at the University of Warwick, UK. Even though there are plenty measures in place to collect and recycle waste cooking oil, for example into soap or biodiesel, data from the UK environmental agency [1] suggest that still large amounts of these end up incinerators. Or they are disposed off into the environment despite the increasing level of sensitisation. Using waste cooking or deep frying oil to make bioplastics which can be used as household’s utensils as well as industrial and biomedical plastics will help create an alternative use of waste cooking oil. This is also likely to aid sensitisation programmes such as a suggested ‘waste oil to household plastic campaign’. The Polyhydroxyalkanoate (PHA) family of polyesters is synthesized by a wide variety of bacteria as an energy source when their carbon supply is plentiful. Poly 3-hydroxybutyrate (PHB) is the most commonly produced polymer in the PHA family. Currently, growing bacteria in large fermenters to produce high quantities of this bioplastic is expensive because glucose is used as a starting material. Work by a research team at the University of Wolverhampton suggests that using waste cooking oil as a starting material reduces production costs of the plastic. “Our bioplasticproducing bacterium, Ralstonia eutropha H16, grew much better in oil over 48 hours and consequently produced three times more PHB than when it was grown in glucose,“ explained Victor Irorere who carried out the research. “Electrospinning experiments, performed in collaboration with researchers from the University of Birmingham, showed that nanofibres of the plastic produced from oils were also 28 bioplastics MAGAZINE [06/12] Vol. 7
Materials Shaping the future of biobased plastics less crystalline, which means the plastic is more suited to medical applications.“ Previous research has shown that PHB is an attractive polymer for use as a microcapsule for effective drug delivery in cancer therapy and also as medical implants, due to its biodegradability and non-toxic properties. Improved quality of PHB combined with low production costs would enable it to be used more widely. Potential applications include every day articles such as pens, cutlery, mobile phone housings or plastic containers. In agriculture, PHA can be used in seed encapsulation, slow release of fertilizers, making bioplastic mulch films and containers for hothouse facilities. The disposal of used plastics - which are largely nonbiodegradable - is a major environmental issue. Plastic waste on UK beaches has been steadily increasing over the past two decades and now accounts for about 60% of marine debris. If plastic parts made of PHB end up in a marine environment by mistake, they would degrade and not increase this debris. They can however be no solution against littering. “Unfortunately the cost of glucose as a starting material has seriously hampered the commercialization of bioplastics, said Dr Iza Radecka who is leading the research. “Using waste cooking oil is a double benefit for the environment as it enables the production of bioplastics but also reduces environmental contamination caused by disposal of waste oil.“ The next challenge for the group is to do appropriate scale-up experiments, to enable the manufacture of bioplastics on an industrial level. C M Y CM MY CY CMY K www.purac.com/bioplastics magnetic_148,5x105.ai 175.00 lpi 15.00° 75.00° 0.00° 45.00° 14.03.2009 10:13:31 Prozess CyanProzess MagentaProzess GelbProzess Schwarz Magnetic 544.175 purac adv 105x148mm.indd 1 19-03-2012 www.plasticker.com for Plastics • International Trade in Raw Materials, Machinery & Products Free of Charge • Daily News from the Industrial Sector and the Plastics Markets • Current Market Prices for Plastics. • Buyer’s Guide for Plastics & Additives, Machinery & Equipment, Subcontractors and Services. • Job Market for Specialists and Executive Staff in the Plastics Industry www.wlv.ac.uk [1] Waste Vegetable Oil - A technical report on the manufacture of products from waste vegetable oil. WRAP, 2007 (http://en.calameo.com/read/00142079145335bcfca12) Up-to-date • Fast • Professional bioplastics MAGAZINE [06/12] Vol. 7 29
