Team:XMU-China/Implementation
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This year, we strived to alleviate the biofouling problem in coastal areas of China. With the increasing report on red tides and mussel clogging incidents, we felt obliged to provide a feasible and competitive solution to those who suffer greatly from this challenge derived from fouling organisms.
To realize our proposal, we designed and made prototype devices to deal with the algae bloom and the mussel adhesion problem separately.
Each company located in riverside, lakeside and seaside and required large cooling equipment would suffer a great deal from red tide and mussel clogging, represented by power plants. For nuclear power plants, the red tide and mussel adhering can easily cause clogging in the cooling water system, which triggers a series of emergent shutdowns of the whole system and even major safety accidents. The leading solutions are adding chemical or frequent manual clean-ups, which was a meager success and time-consuming and laborious. Thus, our devices are designed as a long-lasting solution with low cost, preventing the damage caused by algae bloom and mussel clogging propagation rapidly.
Being designed for factories that demand a mass of water flow for cooling, the target users of our devices are especially suitable for power plants and stakeholders, who will suffer significant security threats and economic loss when encountering fouling organism outbursts. Among those factories, we targeted nuclear power plants, whose cooling water system plays a vital part in operation safety.
For algae bloom, a floating incubator filled with non-liquid nutrient medium and engineered bacteria was constructed, through which function proteins were secreted from the membrane on the sides of the incubator. P. globosa will be killed by urocanate synthesis when attached by protein his-CBM-HutH (See Designfor details), The gels will form and trigger sediment when protein his-3SpyCatcher and his-3SpyTag attach to colonies of P. globosa.
We aimed at constructing a device to clean mussel adhesion, which is fixed to a two-axis platform on the grille of nuclear power plants. This device would send a certain amount of the culture medium from the store cabin into the culture cabin, feeding the engineered bacteria anchored in different locations on the grille and ensuring the production of functional proteins. The function protein TnaA converts tryptophan to indole, which inhibits the biofilm formation of M. edulis on metal grilles (See Designfor details).There is also a built-in device for OD600 detection inside the culture cabin. The data collected can adjust the amount of culture fluid injected into the culture cabin from the store cabin each time. (See Designfor details)
Besides preventing the adhesion of mussels, a culture medium bath was also designed to remove the mussels already attached to the grilles, which can effectively clean the clogged grilles.
What is more, to achieve real-time surveillance and remote control of the device, a mobile application platform for instrument monitoring and controlling was also developed, in which data exchange between the mobile application and our device via Bluetooth® technology. The data of OD600 collected inside the culture cabin is used to assess the functional status of the device. The status is illustrated as a chart with user-friendly descriptions and operation modes for users to choose from the drop-down list. For more information, please check our Hardware.
In both of our devices, we have to address the danger of engineered bacteria leakage into the natural environment. To ensure biosafety, we designed the kill switch system, which guarantees that the bacteria cannot escape from our device.
A kill switch system was constructed, in which the blue-light was chosen to induce promoter pBLind (See Resultsfor details). Induced by blue light with a specific wavelength range, the promoter is activated to express protein BlrA, producing ROS to damage the bacterial functional organelle and kill cells at last. The blue LED light strips were set at the position where the bacteria would leak through. So if the bacteria try to escape, they will be killed quickly.
Since our products contain genetically modified organisms in the lab, even inside a "containing" device, before production and application beyond the lab, our devices should be extensively tested to ensure our engineered bacteria are safe for humans and the environment.
Besides, a new biosecurity law has already been in force on April 15, 2021, in China. The law establishes a system for biosecurity risk prevention and control, including risk monitoring and early warning, risk investigation and assessment, and information sharing. It also has provisions to prevent and respond to specific biosecurity risks, including major emerging infectious diseases, epidemic and sudden outbreaks, and biotechnology research, development and application. To keep our activities legal, applying for permits and approvals is necessary if we execute our proposed implementation.