Biosafety and security awareness run through our projects. We have researched relevant laws and regulations, policies, conventions and other contents in the two directions of microorganisms and cells respectively. We also attended a biosafety meeting with other teams in Freshwater Bioremediation Alliance to discuss biosafety considerations and suggestions for improvement. We carefully analyzed the possible biosafety risks in our project and put forward corresponding solutions based on the collected materials. Finally, combined with the test data of our laboratory and collaborator companies, we confirm that our project has no major biosafety risks under the existing design.
Microorganisms
First of all, we are engaged in biotechnology research, so we must comply with the Biosafety Law of the People's Republic of China and the United Nations Convention on bacteria or microorganisms. We must take into account biosafety issues in terms of public health, biological resources, ecosystems and biodiversity, take responsibility for the safety of biotechnology research, development and application, and adopt a series of prevention and control measures.
Secondly, Shewanella is not on the list of pathogenic microorganisms in China, especially MR-1 has not been reported to be harmful to people. However, further studies are needed to prove whether it will become a pathogenic microorganism and pose a threat to human health and safety after gene editing.
Thirdly, we have researched gene editing, so we must take into account the control of gene editing by UN conventions and Chinese laws. However, most of them are aimed at human gene editing and pay attention to human ethics. Therefore, gene editing for Shewanella is feasible at present.
Our research group tries to use Shewanella in environmental governance like sewage treatment, therefore we refer to the Soil Pollution Prevention Law of the People's Republic of China and the United Nations convention relating to environmental protection, and find that the development and utilization of science and technology to monitor, reduce or even eliminate organic pollutants are encouraged by the United Nations, and it is also supported by the law in our country.
We try to understand the UN declaration of antimicrobial drug resistance problems from another point, if we use Shewanella in environmental governance like sewage treatment, so whether organic pollutants can be regarded as a kind of microbial drug? If we use this solution for a long time, we may cultivate Shewanella’s resistance to organic compounds, and in the end, excessive use lead to Shewanella flood, which may be a kind of pollution.
Cells
As our research goal is to improve the power generation efficiency of microbial fuel cells (MFC), our experimental operation and other aspects will follow the legal norms and conventions formulated by the People's Republic of China, the United Nations and other international organizations.
First, as mentioned in the UN Sustainable Development Agenda, it is time to promote the decarbonization of energy sources and their accessibility. Cheaper renewable energy technologies and the enhanced role of electricity and digital applications are key drivers for changing the way energy services are delivered. Our project on improving the efficiency of electricity generation from microbial fuel cells offers a new perspective for improving energy efficiency and promoting renewable energy as a way of replacing fossil fuels.
In interviews with companies, our interviewee mentioned that one possible application of our batteries in the current market is decommissioned power batteries. At present, the recycling of power batteries is mainly divided into echelon utilization and disassembly recycling. However, this kind of technology is not mature at present, and the recycling and reuse rate of retired power batteries is still at a low level. Our battery products may improve this situation to some extent.
It is precisely because our project mainly uses Shewanella to reduce silver ions, rather than pure chemical redox reactions, that our battery is mercury-free. Chinese law limits the content of mercury in batteries, and there is also relevant content in the Minamata Treaty. Our project can avoid environmental pollution caused by mercury leakage not only in the experimental process but in the subsequent application.
Although we have seen many national plans to promote the development of new energy fuel cells, microbial fuel cells have not received much attention at the national level in this field. What we hope to see is that soon, the international community will be more concerned about microbial fuel cells and draw a line in the sand to safeguard their development.
Biosafety Meeting
At Freshwater Bioremediation Alliance, we conducted a discussion meeting on biosafety. In this meeting, we exchanged measures to deal with the situation according to the relevant requirements on the official website. To refine and optimise our solutions, we have clarified the standardisation of laboratory practices and the handling of potentially harmful substances. In addition to biosecurity risks, we also communicated other means of risk control in the project management process.
More information about our discussion: Collaborations
Our Solutions
Leakage Prevention
Because of the anaerobic environment required, we planned to design a completely sealed MFC unit. Referring to some existing MFC designs, the effluent passes through a buffer chamber into an anode independent of the external environment, the carbon electrode to which the biofilm is attached is itself designed for biofilm formation and the water body is connected to the outside world through a separate channel to facilitate the adoption of controls. The electrical pathway is the only connection between the whole system and the outside world. Therefore it can prevent the leakage of bacteria and silver ions.
Leakage Solution
For the elemental silver, we will use the standard metal leakage process, in which specific methods and steps are used, the rate of loss of elemental silver in our cells needs to be determined by subsequent experiments, and theoretical estimates will only have a small or very small amount of silver loss, then the treatment process of industrial silver-containing wastewater can be streamlined.
For the strains, on the one hand, a section of pipe containing an ultraviolet lamp could be designed downstream, the power of the UV lamp would not be too high, but of course, further estimates of cost and light attenuation from the effluent would be required here. On the other hand, filtering measures can be taken to reduce leakage. It is also possible to sterilise the leaking environment directly — after all, environmental disinfection measures are now well established during an epidemic. Finally, the native strain comes from nature and we have only enhanced its ability to enrich metal ions, which is less likely to have a serious impact on the environment.
Ending Plant Operation
For strains in the MFC containment vessel, a conventional sterilisation procedure is applied directly, e.g. UV irradiation or alcohol dunking. If there are leaks the bacteria are handed over to downstream disposal.
For elemental silver, we need to work only on the utilisation of the silver-containing wastewater, fixing a part of the silver and subsequently treating the lost part of the nano-silver and silver ions by other processes.
A combined process of "three-stage chemical coagulation + ion exchange" is used to treat silver-containing wastewater. In the secondary chemical coagulation system, the pH of the wastewater is again adjusted to 11, and \(\ce{Ag+}\) and TP are further removed by the addition of \(\ce{CaCl2}\), while the removal of \(\ce{Ag+}\) is enhanced by the addition of a metal trap. In the tertiary chemical coagulation system, the pH of the wastewater is adjusted to 9-10 and the residual dissolved \(\ce{Ca^{2+} }\) is removed by the addition of \(\ce{Na2CO3}\). The effluent from the three-stage chemical coagulation system is filtered into the ion exchange system for deep silver removal, so that the \(\ce{Ag+}\) in the effluent is stabilised at < 0.1 mg/L, thus achieving the simultaneous deep removal of silver and phosphorus
Validating
During our communication with LOTUS, we agreed on a preliminary implementation plan. We talked about biosecurity aspects. Since the Shewanella we use is widespread in soil and ocean, it has been verified in our laboratory to not produce substances that pose a biosecurity risk after proper disposal. The LOTUS laboratory has also verified that if the bacteria and materials enter the downstream device with the water flow, they will also be adsorbed by a small amount of sludge and eventually incinerated, and will not leak into the environment. Therefore it is safe.
References
Biosafety Law of the People's Republic of China: link
Law of the People's Republic of China on the Prevention and Control of Soil Pollution: link
Regulations on Biosafety Management of Pathogenic Microbiology Laboratories: link
Wang, J.-W. et al. A Self-Driven Bioreactor Based on Bacterium-Metal-Organic Framework Biohybrids for Boosting Chemotherapy via Cyclic Lactate Catabolism. ACS Nano (2021) doi:10.1021/acsnano.1c06123.
Jiang, M., Zheng, X. & Chen, Y. Enhancement of denitrification performance with reduction of nitrite accumulation and \(\ce{N2O}\) emission by Shewanella oneidensis MR-1 in microbial denitrifying process. Water Res 169, 115242 (2020).
Political Declaration of the High-Level Meeting of the General Assembly on Antimicrobial Resistance: link
Convention on the Prohibition of the Development, Production and Stockpiling of Bacteriological (Biological) and Toxin Weapons and on their Destruction: link
Stockholm Convention on Persistent Organic Pollutants: link
Minamata Convention on Mercury: link
Sustainable battery cell production: link
Supporting Sustainability and Climate Action: link
Law of the People's Republic of China on the Prevention and Control of Environmental Pollution by Solid Waste: link
The Doe Run Company: link
"National Industrial Resources Comprehensive Utilization Advanced Applicable Technology Equipment Catalogue (2021 Edition) "Supply and Demand Matching Guide No. 4: Power battery recycling technology equipment: link