Shellfish waste, eggshells, and orange peels. Sounds like a recipe for somebody’s food waste bin. However, these are just a few out of many unconventional materials being put to use to make bio-plastics. Here, Liz Gyekye highlights the recent developments in out-of-the-ordinary feedstocks.
Currently, bio-plastics account for around 1% of the total volume of 335 million tonnes of plastics in circulation. They are mostly made from first-generation feedstocks, such as corn or sugarcane. According to trade body European Bioplastics, first-generation feedstocks are the most efficient feedstock for the production of bio-plastics as it requires the least amount of land to grow on and produces the highest yields. However, at the same time, the bio-plastics industry is looking into the use of non-food crops (2nd and 3rd-generation feedstock), such as cellulose, with a view to develop new materials.
New economy materials can consist of either drop-in bio-plastics that have chemically identical structures to conventional plastics like PET or PE, as well as new formulations like polylactic acid (PLA) or polyhydroxyalkanoates (PHA) that have chemical structures unrelated to conventional plastics. These materials can be recycled just like their fossil fuel counterparts.
UK bio-plastics producer Floreon is producing what it describes as “exciting” PLA compounds. Th company’s formulations are based on the combination of traditional PLA with small amounts of other certified compostable (EN13432) biopolymers. This mixture helps to enhance the mechanical properties of Floreon’s PLA. Andrew Gill, technical director at Floreon, tells Bio Market Insights that the company’s PLA can improve properties such as heat resistance in a product. He goes on to say that this opens up a wider range of use for applications for the material.
According to Gill, the new formulation allows PLA to move forward from traditional applications like cutlery and packaging to higher value applications like consumer good products and automotive industry products.
n the past, PLA got a bad reputation for its slow rate of degradability, its inability to mix with other plastics in recycling and its high use of GM corn. However, Gill says the conversation around PLA is now changing. He says there “is more joined up thinking on the matter” with companies that distribute PLA working with composters to get it collected and consumers putting their products in the “right” bin.
There is more good news for PLA. Innovative technologies are focusing on non-edible by-products as the source for bio-plastics. PLA is traditionally created from fermenting sugarcane or sugar beets or through the hydrolysis of wheat, or other starches. Yet, materials like food waste from the food processing industry are currently being analysed by companies. “It’s still in early stages, but we are looking at taking food processing waste and working out the yield of taking that into lactic acid and turning it into PLA,” Gill explains.
PLA is not the only bioplastic having a reinvention, PHA is as well. Research is underway to produce PHA that is derived from microorganisms that feed on seaweed. Israeli scientists based at Tel Aviv University (TAU) are currently doing this. The goal is to develop biodegradable plastic which can be productive without using arable land and fresh water. Alexander Golberg of TAU’s Porter School of Environmental and Earth Science, who is co-leading the project, says that the material can be used in a very broad spectrum of applications including medical, agricultural and car applications.
The world is your oyster/shell
There is a reoccurring theme when it comes to broad spectrums of marine organisms being used to make bio-plastics. Shells from crustaceans like shrimp and lobster are also being studied.
In fact, researchers at Canadian McGill University (@mcgillu) have modified a substance found in crustacean shells called chitin into a polymer called chitosan. Research assistant Thomas Di Nardo says the project is unique because it produces a “long polymer which hasn’t been used before”. Consequently, this creates stronger materials.
In essence, the McGill team add additives to modify the properties of the biopolymers to aim for greater flexibility and resistance to wear. The material is compostable and can be used in biomedical applications. Di Nardo says it can be used for coatings for medical implants or even for drug release formulations where you control how long the drug dose is released into the body.
“IN THE LONG-RUN, WHEN COSTS OF PRODUCTION DECREASE, MAKING ANYTHING FROM PACKAGING TO FOOD CONTAINERS WOULD BE IMPORTANT AS WELL,” DI NARDO SAYS.
All told, millions of tonnes of crustacean waste are produced annually, most of which is landfilled or used as fertiliser. So, it seems like the McGill team is onto a winner. It also appears that US-based university Tuskegee has found success in this space. Dr. Vijaya Rangari, a professor in Tuskegee’s Department of Materials Science and Engineering, is leading a team that has managed to add tiny shards of waste chicken eggshells to bio-plastic in order to create a ‘first-of-its-kind’ biodegradable packaging material that bends and is strong. Rangari says this biodegradable film is suitable for biomedical or food packaging applications.
Canada-based Advanced BioCarbon 3D (ABC3D) is also a company that is using niche products to produce bio-plastics. It is using wood to make bio-plastic filaments for use in 3D printing. The company is using hardwoods to produce its materials. CEO Darrel Fry says that the wood the company typically uses is normally left as residual waste as part of the logging process.
Fry adds that 3D printing will allow the materials market to print materials for homes in the future. He explains: “Homes that are completely finished, which include their own energy-generation systems, battery cells, wiring, and plumbing, all from these materials, but built for a fraction of the cost than it is today.”
All these innovations are moving forward. However, that is not to say that challenges do not pervade the second-generation bioplastic feedstock industry. The main challenges with using biomass is finding adequate amounts in one location. In the McGill project, the crustacean waste would come from different facilities and would need to be transported to one location while kept fresh. However, Di Nardo says there are always “ways around this, but it requires heavy financial investments”.
The problem of finding enough biomass to produce bio-plastics is real. John Williams, technical director at Biobased & Biodegradable Industries Association, also says access to secondary feedstocks is a problem because it is not easily accessible. He explains that one would also need to take these feedstocks through two or three stage processes “that will get you towards a feedstock that is stable enough and consistent enough to actually give you a product that you want”. He adds: “I am not going to say that they are never going to be used, they will be. However, it is going to take some time to get to that point.”
Williams says that a lot of companies have rushed down the bio-plastic route, but are tending to use them in high-volume, low-margin applications like shopping bags. He maintains that bio-PE has no difference in functionality than its petrochemical counterpart – it is the same material, but the carbon comes from a different source. He claims that companies that use it are doing so “simply for the sake of a green message”.
He urges companies to shift their focus from bio to “combinations of petro with bio” in order to offer “more sustainable options at the end of life, with a greener feedstock” and ensure that they will not “mess [themselves] up in terms of economics and processes”.
Ariel Brunner, head of EU policy at environmental NGO BirdLife, is also sceptical of bio-plastics and says that companies and consumers should embrace waste prevention and reduction and not use bio-plastics “as an alibi for not reducing waste or recycling”. Nevertheless, he maintains that bio-plastics can be a positive contribution if they are produced sparingly and “can be recycled”. He also says that there is a challenge of companies taking away second-generation feedstocks from other industries like agriculture in order to use it to make bio-plastics and then you “get the problem of displacement”.
All in all, businesses and academics are recognising their potential to use biotechnological processes to create platform chemicals for the production of bio-plastics. With 2nd and 3rd generation bio-plastics production capacity set to grow from 2.27 million tonnes from today to 4.31 million tonnes by 2022, there are opportunities for this sector, and companies are sure to seize opportunities in this space. By the by, they are taking something people would pay someone to take off their hands – waste – and convert it into something people are willing to purchase – a resource.