This year, WHHS-Pro-China team is dedicated to addressing water quality pollution, particularly eutrophication. Through synthetic biology, we aim to achieve effective purification of water sources. In the initial stages of the project, our ideas stemmed from observations of the surrounding environment, and we confirmed specific goals through field research. During this process, we engaged in in-depth discussions with multiple experts to continuously optimize the project. Additionally, we focus on promoting sustainable agricultural development and raising public awareness of sustainability. To this end, we have organized a series of activities aimed at enhancing awareness of the importance of water purification.
Our project was inspired by a team member's observation of their community pond. We found that the water quality has deteriorated significantly, with a thick layer of algae covering the surface and almost no visible fish or other organisms, indicating severe damage to the ecosystem. This situation prompted us to think about the root causes: what factors have led to such a decline in the pond's environment? We aim to conduct in-depth research to identify the main factors affecting water quality and seek practical solutions.
We held a group discussion and reviewed a large amount of online information, discovering that the causes of water pollution are varied. Among them, the excessive discharge of phosphates is one of the main factors leading to eutrophication. However, the community pond is just one example and cannot fully reflect the complexity of the issue. Therefore, we decided to select a lake for a field investigation to obtain more comprehensive data and insights, allowing us to better understand the specific circumstances and influencing factors of water quality pollution.
We conducted a field investigation at the Nanhu Park Greenway in the Hongshan District of Wuhan. Here, we found that a small pond by the lake was severely eutrophied, and we even discovered dead fish along the shore of Nanhu Lake. This phenomenon was shocking, and we spoke with a resident who was walking by the lake. She expressed her deep concern about the eutrophication, recalling how clean the water used to be in her childhood, and lamenting that this situation seems unchangeable now. This made us even more aware of the urgent need to draw attention to the importance of protecting water sources and improving the ecological environment.
We discussed our observations with teacher Duan, a master's student in aquatic biology at Wuhan University. He pointed out that the small pond beside Nanhu Lake is severely affected by extreme eutrophication. The water in Nanhu Lake appears green and translucent, which, although not covered by thick algae, is still indicative of eutrophication, mainly due to the outbreak of microalgae that can lead to the death of aquatic organisms. Currently, the government has initiated a water purification project, treating wastewater through sewage treatment plants and discharging the purified water back into the lake to improve water quality. Our conversation with teacher Duan made us realize that measures must be taken to address the issue of eutrophication in the water source.
We had in-depth discussions with our chemistry teacher, Ms. Xia, and Professor Kira Homola from UCLA, gaining insights into the complexities of current chemical methods for phosphate resource recovery. These methods struggle to find a balance between cost, efficiency, and sustainability.
We also learned about the limited and non-renewable nature of phosphate resources. Although excessive phosphate emissions have brought environmental problems, from a global resource perspective, phosphate is a limited and non-renewable resource. Currently, the world's main reserves of phosphate ore are concentrated in a few countries, including Morocco, China and the United States, and these reserves are being consumed rapidly. With the growth of global agricultural demand, the continued consumption of phosphate resources may trigger a serious resource crisis in the next few decades, directly affecting agricultural production and food security. Therefore, how to effectively manage, recycle and reuse phosphates has become the key to solving environmental problems and resource shortages.
Therefore, we decided to adopt biological methods to address the issue of eutrophication in water sources, hoping to achieve a more efficient and sustainable solution. Through biotechnology, we aim to better tackle this environmental challenge.
We communicated with Master’s student Duan from Wuhan University, sharing our group discussions and field investigations. He mentioned that the excessive discharge of phosphates is one of the main factors leading to eutrophication. Regarding phosphate treatment, Duan suggested that we consider modifying microorganisms to absorb phosphates and then process these microorganisms to achieve pollution remediation.
Based on Duan's advice, we reviewed a lot of literature and found that phosphate-binding protein (PBP) is an ideal choice, as it can effectively adsorb phosphates. Thus, we designed an experiment to utilize Escherichia coli to produce this phosphate-binding protein, aiming to address the issue of water eutrophication.
Phosphate-binding proteins (PBP) can effectively absorb phosphates, but since this protein is synthesized inside the cells of E. coli, we need to design a method for phosphates to be transported into the cells. To address this, we consulted with Master’s student Du from Wuhan University, who suggested an alternative approach: instead of transporting phosphates into the cells, we could display the phosphate-binding protein on the cell surface for direct phosphate adsorption.
After discussion, we decided to design a fusion of the Invasin Protein (INP) with the high-affinity phosphate-binding protein (PBP), allowing PBP to be stably displayed on the surface of E. coli cells. This way, we can achieve efficient phosphate absorption.
We interviewed two teachers from the Resource and Environment College at Central South University, who pointed out that our project has the potential to reduce water eutrophication, decrease ocean pollution, and protect marine habitats and biodiversity. However, they also emphasized the importance of project safety, particularly the risk of ecological imbalance and potential impacts on non-target organisms due to improper application of the technology.
This discussion made us aware of biosafety issues. Since we are using genetically modified E. coli, any leaks could disrupt the microbial systems in lakes or oceans.
At the same time, we also noticed that engineered strains treated with extreme acid, very low acid or high temperature faced a large number of deaths, resulting in high costs and limited adsorption capacity.
We held a series of group discussions. Initially, we considered using a suicide system to ensure that the bacteria self-destruct after performing their function, but this was clearly impractical, as it would result in the re-release of absorbed phosphates into the water. Therefore, we began exploring the possibility of immobilizing these bacteria onto a material to facilitate the adsorption and recovery of phosphates while ensuring both safety and efficiency.
We discussed materials with Teacher Liang from the Materials Science Department at Wuhan University. He pointed out that having our bacteria adhere to a specific material is technically complex, whereas attaching the phosphate-binding protein to a material is relatively straightforward. He recommended using agarose beads, a commonly used biomaterial, to bind the produced protein. Additionally, the size of the agarose beads can be adjusted according to needs, thereby enhancing the adsorption efficiency for phosphates.
In our subsequent research, we adopted Teacher Liang's suggestion and decided to combine the phosphate-binding protein with NHS-activated agarose beads. These beads will be used to treat wastewater, achieving efficient phosphate adsorption. Once the beads have absorbed a sufficient amount of phosphates, we can elute and recover the phosphates by adjusting the pH. This approach not only improves processing efficiency but also effectively ensures ecological safety.
We discussed our optimized project with Dr. Yang Xiaojie from the Institute of Environmental Ecology at the Chinese Academy of Sciences, focusing on the project's safety issues. She emphasized the need to consider the impact of different materials on water sources and the potential hazards that could arise if our project were applied to external environments and the devices were damaged.
Therefore, in our project application, we envision implementing it in wastewater treatment plants. Once the beads have adsorbed a sufficient amount of phosphates, we can elute and recover the phosphates by adjusting the pH. As the project develops, we will gradually build complete facilities to ensure safe and effective treatment of external water sources.
We interviewed Mr. Deng Qing from the Xingche Public Welfare Environmental Organization, who shared his efforts in protecting lake water sources, including reporting factories that discharge wastewater. Mr. Deng pointed out that we must take a dual approach: on one hand, we need to stop factories from polluting and raise public awareness about water source protection; on the other hand, we must develop technologies for water purification.
During our previous field research at the Nanhu Park Greenway in Hongshan District, Wuhan, some passersby expressed concerns about the situation but felt powerless to make a change. Phosphorus pollution is not only related to the over-extraction of phosphate minerals and industrial wastewater discharge but is also closely linked to the discharge of domestic wastewater and the excessive use of fertilizers and pesticides in agriculture. Therefore, we plan to carry out a series of activities aimed at raising public environmental awareness and promoting actions for water source protection.
We visited a sewage treatment plant to learn about their work in phosphorus treatment within wastewater. The facility manager informed us that they not only handle wastewater treatment but also take on the task of purifying lake water, returning the treated water back into the lake. During the lake water treatment process, they also incorporate microbial treatment steps, which piqued our interest. The manager expressed great confidence in our project, believing that if our technology is successfully developed, we could definitely collaborate with them to achieve phosphorus resource recovery.
We held an event at Donghu in Wuhan to raise public awareness about protecting water sources. During the event, participants expressed their support for our project, emphasizing the growing necessity of lake water purification. We provided information on household wastewater, reminding everyone not to casually dispose of laundry wastewater or food scraps by the lake, as this can effectively protect the water source. Participants showed their support and committed to being more mindful in the future.
At the same time, we also discovered that the water pollution issue at Donghu is quite severe, which further deepened our sense of responsibility and urgency to address water quality pollution. We hope that through our continued efforts, we can draw more attention to the importance of water source protection.
We also created posters and conducted interviews to promote our project and raise awareness about sustainable development. People expressed their support for our initiative. We aim to make everyone realize that water purification is closely related to their daily lives. By raising social awareness, we advocate for reducing the casual disposal of everyday waste, which not only helps to lower phosphorus pollution but also fosters public understanding and practice of sustainable development and harmonious living with nature. We believe that only through collective participation can we truly achieve water resource protection and ecological improvement.
We conducted research with the WHHS-China team in a tea garden and discovered that water source pollution also exists in the surrounding area. The reservoir used for irrigation has already shown signs of eutrophication. This finding opens new directions for our project's application, indicating that our technology can not only purify lake water sources but also treat water in agricultural reservoirs to prevent further pollution from spreading to the surrounding soil.
More importantly, the recovered phosphates can be used as agricultural fertilizers, effectively replenishing soil nutrients while promoting phosphate reuse and reducing waste generation. This circular use not only helps lower agricultural costs but also promotes sustainable agricultural development and enhances the health of agricultural ecosystems. Through our project, we aim to improve water quality while providing strong support for the sustainable development of agriculture.
Human practice activities are crucial as they clearly demonstrate how we identify problems, solve them, optimize project plans, and fulfill our responsibilities to society. In this process, we aim to develop low-cost solutions that ensure no secondary pollution while purifying water sources and recovering phosphate resources. The recovered phosphates will be used for fertilizer production, contributing to sustainable agricultural development. We hope our project will not only exist as a scientific research endeavor in the laboratory but also truly benefit society and promote dual sustainability in both ecology and the economy.
