Human Practices
Introduction
As a high school team, the concept of Human Practices guided us step by step in improving our design. Human Practices ran through all of our actions—it influenced our project design and iteration, shaped our understanding of environmental pollution and wastewater treatment, and even provided us with valuable advice on academic writing and scientific communication. We received support from many professionals and researchers, which constantly reminded us of our responsibility and the real-world value of our actions.
Our Human Practices work targeted iGEMers, researchers, industry regulators, practitioners, and wastewater treatment companies.
Our HP model is: Problem → Stakeholder Engagement → Knowledge Extraction → Discussion & Improvement → Action & Feedback.
This two-way iterative cycle helped us extract the most relevant insights from vast amounts of information and guided us to further optimize our project.
Next, we will present our Human Practices outcomes, organized by “Problem.”
How We Focused on Wastewater Treatment
1. Stakeholder Engagement
Our interest in environmental issues led us to form an iGEM team, but at first, we didn’t know which specific issue to focus on. We contacted two former iGEM team leaders, Tianyue Dai and Zhichen Guo, and held online discussions. We shared our confusion about project directions, and they provided:
1. References to past iGEM projects
2. Academic literature
3. Time management advice for high school teams
4. Analyses of recent Environment Track projects
2. Knowledge Extraction
①Focus on toxic substance degradation functions
②Address water pollution and remediation
③Two key papers provide frameworks for hazardous material degradation design (Cong Su, 2025; Henry H. Lee, 2019)
3. Discussion & Improvement
After extensive literature review, data research, and analysis of previous iGEM projects, we initially decided to design a system for degrading harmful substances in wastewater. However, we found that different teams used different chassis organisms (E. coli, yeast, Bacillus, etc.). Choosing a chassis became a new discussion point.
Extended Problem: Choosing a Chassis
1. Stakeholder Engagement
We reached out again to Zhichen Guo, sharing our preliminary design through a PPT presentation and raising our questions about chassis selection.
2. Knowledge Extraction
· E. coli offers clear advantages:
o Genetic plasticity — It has a mature genetic toolkit and modular assembly system, which allows us to efficiently insert and optimize degradation gene clusters.
o Natural resistance mechanisms — With existing efflux pumps and sodium/proton antiporters, E. coli can handle toxic intermediates and survive under stress conditions.
o Cost-effectiveness — It is inexpensive to culture, grows quickly, and is a standard model organism in laboratories worldwide.
These advantages made E. coli the most practical choice for our project.
3. Action & Feedback
We decided to use E. coli as our chassis and target aromatic hydrocarbons for degradation, redesigning our engineered strain accordingly.
Risks of Biocontainment and Substrate Pollution in Wastewater Treatment
1. Stakeholder Engagement
In China, companies must follow strict national discharge standards. To better understand these, we consulted Mr. Li, a nationally certified environmental impact engineer with years of experience.
We presented our preliminary design, and Mr. Li provided extensive advice from the perspective of both regulation and industrial practice.
Fig .1 | We had an online meeting with Mr. Li
2. Knowledge Extraction
①Innovation in biotreatment technologies is urgently needed. While some companies already use biological methods, there are no precedents for E. coli-based degradation, so our plan has strong practical value.
②Wastewater is processed through multiple pools, each targeting specific pollutants. No method currently treats multiple pollutants simultaneously—designing a “universal strain” could significantly reduce costs.
③Biofilter systems are complex and produce large amounts of toxic sludge, which poses diffusion risks as hazardous waste. This is a major industrial challenge that our design could address.
④Experimental data should be evaluated against national discharge standards (e.g., GB8978-1996, GB 31570—2015, GB 31571—2015).
⑤Project presentations should lower communication barriers for non-synthetic-biology audiences, using more accessible language.
⑥Teams must consider treatment costs.
⑦Most factories use pretreatment before wastewater treatment—our design should reflect actual industrial processes.
Fig .2 | Mr. Li provided the national emission standard documents.
3. Discussion & Improvement
· Result 1: Instead of designing a single-function strain, we could develop a modular framework: by swapping different degradation gene clusters, one engineered strain could target multiple pollutants.
· Result 2: Inspired by traditional wastewater treatment, we added biosafety mechanisms: a closed physical filter box and a temperature-sensitive kill switch:
o Physical containment filter box: We designed a closed filtration device to confine our engineered bacteria within the wastewater treatment system. This minimizes the risk of microorganisms leaking into the natural environment while still allowing pollutant degradation to occur efficiently.
o Temperature-sensitive kill switch: We introduced a genetic circuit that activates cell death under non-permissive conditions. Specifically, when the bacteria are outside of the controlled wastewater environment (e.g., exposed to lower temperatures), the system triggers toxin accumulation, ensuring that escaped bacteria cannot survive.
· Result 3: To improve communication, we began refining our PPT language for non-scientific audiences, even experimenting with AI tools for phrasing.
4. Action & Feedback
· For Result 1, we reviewed more literature and validated our framework experimentally with aromatic hydrocarbons.
· For Result 2, we integrated a kill switch system into our design.
· For Result 3, we optimized presentation language, added more visuals, and included updated kill switch descriptions.
Addressing Environmental Stress
1. Stakeholder Engagement
We consulted Professor Wang from the Institute of Chemistry, Chinese Academy of Sciences.
Fig .3 | We had an online meeting with Prof. Wang
2. Knowledge Extraction
①Since our E. coli must function in wastewater, high salinity and toxicity may limit performance.
②We should add more literature references to clarify the hazards of aromatic hydrocarbons.
③It is important to distinguish aerobic vs. anaerobic traits—can our design address both?
3. Discussion & Improvement
· Result 1: Add a controllable resistance module to ensure E. coli stability in toxic wastewater using two key systems controlled by a quorum sensing regulatory circuit:
o NhaA Na⁺/H⁺ antiporter: helps cells survive in high-salt and alkaline conditions by exchanging sodium and protons, maintaining intracellular ion balance and pH stability.
o AcrAB–TolC efflux pump: expels a wide range of toxic compounds, including aromatic hydrocarbon intermediates, detergents, and antibiotics, reducing intracellular stress.
· Result 2: Expand literature review to strengthen background on aromatic hydrocarbon hazards and microbial traits.
4. Action & Feedback
For Result 1, we incorporated a tunable resistance function into our engineered strain. Our resistance module was regulated by a quorum sensing system (LuxI/LuxR–pLuxRA). At low cell density, resistance genes remain largely inactive, minimizing energy burden. As cell density increases, quorum sensing activates the promoter, leading to expression of the NhaA antiporter and AcrAB–TolC efflux pump. This design ensures that E. coli maintains normal growth when stress is low, while gaining enhanced tolerance under toxic wastewater conditions.
We also updated the Background section with new references and improved our PPT content.
Considering Product Operation Guidelines
1. Stakeholder Engagement
We consulted Dr. Zhu from the Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, who has long been engaged in water quality monitoring of Lake Taihu.
Fig .4 | We had an online meeting with Dr. Zhu
2. Knowledge Extraction
①Dr. Zhu gave us a lecture on the relationship between environment and water quality, sharing major cases of water pollution and remediation from coastal and southwestern regions of China.
②He emphasized that both scientific practicality and industrialization processes must be taken into account.
③If our design were to be put into use, a clear set of operation manuals or protocols would be necessary for real-world application.
3. Action & Feedback
Based on this advice, we added an operation manual to our project design. Please check the PDF for details.
Enterprise Interviews
1. Stakeholder Engagement
We interviewed representatives from Sinopec Shijiazhuang Refining & Chemical Company, including Mr. Bian from the Environmental Protection Department, and visited the company’s wastewater treatment facilities. Mr. Bian explained the treatment process and the company’s requirements for project procurement.
2. Knowledge Extraction
①Industrial wastewater treatment systems usually have one treatment pool for one pollutant only. Our engineered strain, which can target multiple pollutants, was recognized as a potential advantage by the company.
②The wastewater treatment product market is highly competitive, with many suppliers; therefore, product cost control must be considered.
③The company also raised the question of whether our design should be developed as open-source or proprietary technology.
3. Action & Feedback
We incorporated cost considerations into our project framework and, in subsequent design iterations, also took into account the specific substances and requirements (inorganic pollutants containing N and P.) mentioned by the enterprise.