Team:Edinburgh/Human Practices/Circular
How we fit into the Circular Bioeconomy
The concept of the bioeconomy was first introduced in the European Commission’s action plan ‘Innovating for a sustainable growth: a bioeconomy for Europe’ [3].
The Definition of Bioeconomy:
‘Production of renewable biological resources and the conversion of these resources and waste streams into value added products, such as food, feed, bio-based products and bioenergy’ [3].
In terms of the bioeconomy strategies, the ‘Circular Bioeconomy (CBE)’ concept was then introduced and has aroused great attention to this (Figure 1). So far, only limited attention has been paid to the end-of-life bio-based products [4]. Furthermore, in many countries, the agricultural sector currently determines how the bioeconomy is discussed and negotiated at a political level, nationally and internationally [4]. Therefore, our research on how to better deal with the waste of Keratin, Chitin, Cellulose and PET is crucial and meaningful.
Figure 1 The circular bioeconomy and its elements. (Source: Stegmann, P et al (2020). [4] )
As shown above, the main reason to tackle waste problems is to conserve space in landfills and reduce the need to build more landfills as these could lead to significant air and water pollution. In order to understand more specifically why our SuperGrinder is good for our planet and us, we should focus on the different compounds which could be potentially recyclable and give an estimate of their impact on Earth.
Keratin waste
Keratin is a waste stream produced in large part by the poultry industry, being present in feathers. Feather-waste is ubiquitous as 7% of a chicken's weight is feathers and nowadays there are 114.28 million tons of chicken being produced [5]. The SuperGrinder offers an alternative process to get rid of an otherwise problematic waste stream, that is even being dumped on the streets in parts of the world. There are also other major sources of keratin (see Figure 2), however most are less common or just not collected on a large scale.
Figure 2 Main sources of keratin: (A) Bird’s beak; (B) animal hair; (C) human nail; (D) horn; (E) human hair; (F) hoof; (G) nail; (H) chicken feather: the hosts for these sources include human, bird and animal (Source: Kumawat et al,2018 [6]).
We also designed a flowchart explaining the supply chain of keratin (see Figure 3).
Figure 3 Flowchart demonstrating the keratin supply chain and potential end applications
There are however already multiple different processes and products that are used to recycle keratin. Keratin is used in various hair products as hydrolyzed form [7]. By adding wood chips and bacteria to feather waste one can compost it into fertilizer, this is a simple and relatively cheap solution to getting rid of feathers [8]. Another common way to process feathers is by cooking, drying and grinding them into a feather meal, which is used as an additive to animal feed, because of its high nitrogen and protein content [9].
Chitin waste
Seafood waste has been a huge problem worldwide, accounting for billions of dollars of losses every year. Annually the industry generates more than 100 tons of waste, most of which is discarded or turned into low-value products. Recycling of seafood waste has not been established as a widespread practice and a large amount of this waste is discarded directly into the environment. Nonetheless, some of these raw materials can be used to produce materials with high value. For example, chitosan is a polymer obtained by deacetylation of chitin, found in molluscs, insects, exoskeletons and arthropods. Chitosan has antibacterial, antifungal characteristics which could be used for application in agriculture, food, cosmetics, or textile industries. Most current methods for extraction of chitin are based on chemical extraction, which could be harmful to the environment or are expensive and energetically inefficient. To process and make such products out of seafood waste, new processing and management techniques are needed. We believe that using the SuperGrinder we could improve the current extraction methods and provide a greener, more sustainable alternative.
Cellulose Waste
Lignocellulosic biomass is an abundant and renewable resource from plants that are mainly composed of polysaccharides such as cellulose and hemicelluloses along with lignin. However, they are very difficult to degrade due to multiple factors such as structural factors including its crystallinity, degree of polymerization, composition, amongst many others. Unfortunately, the most commonly used methods to degrade them are unsustainable and not cost effective as they’re either burned or treated with harmful chemicals which are harmful to the environment and support an unsustainable practice. To solve this issue, our SuperGrinder aims to develop a mechano-enzymatic machine that uses enzymes immobilized to silica to degrade cellulose to amino acids which could be used for other applications. This is a more sustainable and renewable method to degrade lignocellulosic biomass.
PET Waste
There has been an increase in plastic use throughout the years. Plastics are used to manufacture a variety of everyday-use items such as trash, grocery bags, bottles and containers. However, they are very hard to degrade and can remain intact in the environment for many years. On the other hand, the process to produce plastics are non-renewable as they are made from chemicals such as coal, gas and oil that contribute to the production of greenhouse gases. Most methods to get rid of plastics are unsustainable such as burning which contributes to greenhouse gases emissions along with littering in landfills which takes up space and is harmful to wildlife. Overall, plastics are one of the world’s pressing environmental issues and a sustainable way to degrade them is urgently needed. A common plastic used is PET and it could be biologically degraded by the PETase enzyme. This idea will be implemented in our SuperGrinder where the PETase enzyme will be immobilized on silica beads for a better sustainable method to degrade PET.
The problem of plastic pollution Source GreenPeace
So...why do we need the SuperGrinder?
Although these challenges have previously been addressed by various recycling techniques and grinding methods, we believe that our SuperGrinder model is unique as it has the potential to cut down on costs and significantly increase yield. This would result in more of the desired compounds being recycled and converted into high value products, which would increase our way towards a circular economy. To convey our message and confirm the strong need for a recycling technique, we tried to contact the stakeholders in related fields.
- 1. Zaman AU (2016) A comprehensive study of the environmental and economic benefits of resource recovery from global waste management systems. J. Clean. Prod. 124: 41–50
- 2. Ellen MacArthur foundation (2019) CITIES AND CIRCULAR ECONOMY FOR FOOD
- 3. European Commission, E. (2012). Innovating for sustainable growth: A bioeconomy for Europe. https://doi.org/10.2777/6462
- 4. Stegmann, P., Londo, M. and Junginger, M. (2020). The circular bioeconomy: Its elements and role in European bioeconomy clusters. Resources, Conservation and Recycling: X. 6(January), 100029. https://doi.org/10.1016/j.rcrx.2019.100029
- 5. https://www.statista.com/statistics/263962/number-of-chickens-worldwide-since-1990/
- 6. Tarun Kumar Kumawat, Anima Sharma, Vishnu Sharma and Subhash Chandra (December 19th 2018). Keratin Waste: The Biodegradable Polymers, Keratin, Miroslav Blumenberg, IntechOpen, DOI:10.5772/intechopen.79502
- 7. https://www.keenanrecycling.co.uk/recycling-services/organic-recycling/
- 8. https://core.ac.uk/download/pdf/20272682.pdf
- 9. https://en.wikipedia.org/wiki/Feather_meal