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Inspiration

The selection process of our iGEM project ‘Remedye’ required us to have weekly meeting since the end of February 2019. In the first three weeks, each team member had the task of researching in the literature and from previous iGEM projects, and the opportunity to present an idea to be discussed. Each week we had feedback from our supervisors assessing the pool of ideas. In the fourth week, we voted for the best idea. It was essential for us that each member of our team had an individual subproject, which he or she was happy to work on. Remedye was selected because we identified that the pollution derived from the extensive use of azo dyes in the textile industry is a serious problem for the environment and a potential threat for human health. The previous work carried by Goodbye Azo Dye UCL 2014 team was a fundamental base in our design thinking process, and we also took inspiration from the SHSBNU China 2018 team, Biofilm x Laccase.

We were determined to increase the project scope by (I) improving the dye degrading enzymes bioactivity using directed evolution, (II) construct heavy metals biosensors to test azo dye pollution, and (III) develop enzyme delivery systems (extracellular immobilization for creating dye degrading biofilms, intracellular immobilization creating ghost shells, and immobilization in organic biomaterial as biochar). Additionally, we were inspired by the circular economy philosophy developed by many thinkers including Gunter Pauli and Ellen MacArthur; in conjunction with state-of-the-art synthetic biology companies such as Bolt Threads and Spiber in the biomaterials industry. This guided us to envision the use of dye waste as a resource for (IV) producing valuable biomaterials such as synthetic silk. To ensure technical progress we segmented our team into four tracks: Improvement of Dye-Degrading Enzymes, Biosensors, Enzyme Immobilization, and Synthetic Silk Production. Each division had their own milestones to work in the development of biobricks, and the responsibility of reporting the advancements to the internal team and supervisors. We also assigned individual roles for specific tasks aligned with the skills of each team member. For example, Nico oversaw the logo and team identity, Nathan led the minute reporting and lab best practices, Mirren did everything related to programming, and so on. Regarding human practices and public engagement, everyone took a proactive role. Finally, we came with an integral proposal for a real-world problem. Remedye forced us to get out of our comfort zone by planning and executing an ambitious wet lab project and reaching out to external stakeholders asking for their feedback. Our goal for Remedye, in addition to developing new characterized biobricks, was to understand the big picture of the azo dye pollution problem and to propose a solution using the power of synthetic biology.

Project Description

Synthetic Dyes In 1856 Sir William Henry Perkin failed an experiment that changed the history of dyeing consumable products as textiles, food, pharmaceuticals and ink [1]. While Perkin was attempting to produce quinin, a chemical used for treating malaria, his beakers were left filled with a dirty brown sludge. After cleaning the beakers with alcohol, he noticed a very intense fuchsia-purple dye. He called the dye “mauveine” and was the first synthetic dye in history. Before Perkin’s discovery, dyes and pigments had to be sourced from plants, metals, minerals, or insects, often at significant cost and effort. In contrast with some natural dyes, Mauveine was characterized for allowing a permanent stain. The work of Perkin lead to the discovery of several synthetic dyes (mainly produced by petrochemicals) that would make bright and inexpensive synthetic colors available to the masses. However, a family of synthetic dyes named azo dyes has been subject to research and discussion since some of these molecules release mutagenic and carcinogenic aromatic amines to the environment. The Problem With Azo Dye Azo dyes are used in several industries due to their high levels of photostability and relatively low cost. Their high adoption rate and extensive usage in the industries – particularly the textile industry – has led to high levels of pollution in textile producing regions. Azo dyes make up 70% of commercial dyes, accounting an estimated of 700,000 tons produced each year [2], [3]. Annually, around 3 × 105 tons of textile dyes are discharged into wastewaters worldwide [4]. According the World Bank, fabric dyes and treatments are responsible for an estimated 17 – 20% of total industrial water pollution and roughly two-thirds of all these industrial dyes belong to the group of azo dyes [1]. Some azo dye intermediates (aromatic amines) are highly toxic and carcinogenic, resulting in an existing threat for the environment and human health. Given the enormous volumes of water polluted with azo dyes released by factories without a proper treatment, azo dye pollution poses a massive problem in heavily textile industry-dependent countries, such as China, where up to 90% of the local groundwater is estimated to be polluted, to which azo dyes greatly contribute [5]. A recent study investigated the mutagenicity of 397 non-regulated aromatic amines potentially released from the 470 known textile azo dyes. The researchers identified 40 mutagenic aromatic amines from approximately 180 different parent azo dyes, indicating that mutagenic aromatic amines in textile azo dyes are of much higher concern than previously expected [6]. The European Union has banned only 24 aromatic amines derived from azo dyes commonly used in clothing textiles as carcinogenic [6]. This legislation is becoming a common standard in other major textile producing regions in Asia. For example, in China 88% of the textile producers have upgraded their wastewater equipment to stay in line with the regulations and avoid being shut down [7]. Unfortunately, regulations are increasing costs for manufacturers, but prices offered by brands/sourcing agents are not reflecting this. As a result, manufacturers are being squeezed through low margins and the majority are currently carrying the costs of shifting to cleaner and circular production [7]. Indeed, over 50% of respondents have made significant CAPEX investments of more than ~USD300,000 to upgrade their factories [7]. This is pushing established textile manufacturers to invest on innovative solutions while at the same time maintaining competitive margins to survive in the market. The current methods used to treat azo dye pollution can be split into two categories – chemical and physical. Both methods are relatively costly and can cause secondary pollution. Bioremediation using dye-degrading enzymes may offer a better, less expensive and more robust option for textile dyes remediation.

The Remedye Solution Remedye is tackling the azo dyes pollution problem by (1) improving the enzymatic function of azo dye degrading enzymes, (II) immobilizing the enzymes as a delivery system for application, (III) developing biosensors to test contaminants in waste effluents, and (IV) the production of synthetic spider silk in bacteria with the potential use of aromatic amines (azo dyes sub-products) as a carbon source. We propose an integral approach of our research to create dye-polluted water treatment plants as part of textile facilities, where the outputs are clean water and synthetic silk. The main goal of this proposal is to reduce the environmental impact of azo-dye pollution and to explore novel technologies to promote a sustainable textile industry using circular economy principles. References [1] R. Kant, "Textile dyeing industry an environmental hazard," Natural Science, 2012. [2] P. J. Wakelyn, "Health and safety issues in cotton production and processing," in Cotton: Science and Technology, 2006. [3] F. M. Drumond Chequer, G. A. R. de Oliveira, E. R. Anastacio Ferraz, J. Carvalho, M. V. Boldrin Zanoni and D. P. de Oliveir, "Textile Dyes: Dyeing Process and Environmental Impact," in Eco-Friendly Textile Dyeing and Finishing, 2013. [4] C. J. Ogugbue and T. Sawidis, "Assessment of bio elimination and detoxification of phenothiazine dye by Bacillus firmus in synthetic wastewater under high salt conditions," Journal of Applied Sciences, 2011. [5] W. Bank, "COST OF POLLUTION IN CHINA," The State Environmental Protection Administration, Beijing, 2007. [6] B. J. Brüschweiler and C. Merlot, "Azo dyes in clothing textiles can be cleaved into a series of mutagenic aromatic amines which are not regulated yet," Regulatory Toxicology and Pharmacology, 2017. [7] C. W. Risk, "Insights from China Textile Manufacturers: Gaps to Overcome for Clean & Circular Fashion," 2017.

Contact Us Edinburgh OG Peter Wilson Building University of Edinburgh edigemmsc@ed.ac.uk