Team:NUS Singapore/Safety

iGEM Wiki

iGEM Wiki



While engineering organisms to fulfil varying functions is getting simpler and more effective by the day, one major hurdle of using engineered organisms, in particular bacteria, is the need for effective biocontainment. Thus far, many biocontainment strategies have been proposed but little progress has been made to effectively prevent the undesired release of engineered bacteria into the natural environment.

To ensure the safety of our project to the environment, we have designed a plasmid retention system which effectively locks our system in our engineered cells. We adhered to strict lab safety practices throughout the project and actively sought the advice of safety experts to shape our project.

Safe Project Design

With any system that is to be deployed outside the laboratory, there is a risk of release of the engineered organism. As our project involves working with farms and agricultural stakeholders, we took extra precaution to ensure that the system had effective biocontainment to minimise risks.

Taking this into account, we ensured that our final design does not involve the deployment of the engineered chassis outside of the bioreactor vessel. The bioreactor is in fact, designed to have built-in spill/leak redundancy as a form of physical/environmental containment measure. Additionally, the production chassis will incorporate a blue-light inducible flocculation gene circuit that will result in the chassis flocculating to the bottom of the reactor vessel. Only the cell-free supernatant will be siphoned off from the top to prevent uptake of the chassis. Secondary biocontainment is achieved using a blue and red light-inducible AND gate that will trigger the expression of endonucleases to destroy any chassis organisms that were not flocculated. Tertiary biocontainment is also achieved as we filter the product, human beta defensin, from the reactor through a 0.22-micrometer membrane to prevent any remaining chassis organism from being retained in the final product.

Safe Laboratory Practices

Risk assessment was performed before every experiment and testing, and adequate protection such as appropriate attire and eye-protection mandates were enforced during the testing process of all the hardware.

Members were cautioned against staring directly into the bright LED lights, and the production collection vessel containing the UV light was designed to be an enclosed holder with the UV light facing away from the user to avoid direct exposure of UV light to our members.

All the professors, supervisors, and advisors part of our team, reviewed our protocol documents before we began our experiments. All students performing the experiments were required to complete safety training and were oriented by a safety officer before the conduct of the experiments. All the experiments were also conducted under the supervision of experienced research fellows at the NUS Engineering Biology Lab and NUS SynCTI who have worked with both E. coli and S. cerevisiae extensively, ensuring that all the protocols are carried out safely.

Human Practices on Safety

Our human centric approach to the pest control solution requires us to both develop a safe biopesticide for public health as well as the environment and do so in a safe and responsible way.

To understand the safety profile of our biopesticide - human beta defensin - and seek experts’ opinions on possible safety risks and preventive measures, we approached Singapore Food Agency and Genetic Modification Advisory Committee of Singapore, the regulatory bodies for the registration and use of pesticides and for the release of Genetically modified organisms, respectively.

The secretariats of GMAC, Ms Kang Li Xin and Ms Mazlina Banu Jaikubali, assessed that our human beta defense is likely to be approved for release by GMAC as it is a purified protein that naturally exist in human body. They also added that our modification, being in yeasts, would not pose an ethical risk, although further consideration and approval would be required on the safety of our engineered organisms. Nonetheless, they suggested minimizing the risks of any release of genetically engineered yeasts, as it poses threats to the environment with the possibility to affect other species, especially mammals.

We then consulted the experts’ opinions on our preventive measures of GM yeasts leakage - protein purification, kill switch, and automation of the decentralized bioreactors. They confirmed that purification and kill switch largely reduce the risks of leakage and suggested exploring further purification steps to supplement flocculation to meet a higher safety standard. They also pointed out the decentralized bioreactors at farms particularly needed both careful hardware design and education to ensure biosafety. While confirming that an automatic bioreactor design helped to reduce human errors, they further suggested educating the farmers, requiring PPE and monitoring the decentralized bioreactors.

The secretariats and scientists from SFA, provided feedbacks with special regards to the safety of applying pesticides in indoor farms. They invited us to design our biopesticides with the environment of indoor farms in mind, which is often a closed, compact space close to residential areas. In this ventilation condition, we should not design a biopesticide with a spraying application method. Instead, we should design it such that it treats the growing media or the seeds.

The feedbacks from the safety experts all provided insights that we took very seriously for the safe, responsible designs of our product. Our final design is an automatic production of human beta defensin with purification and kill switch. For how we incorporated the experts’ input into our product design, please see our human practices page.

As we developed a safe product for our stakeholders, we also ensure we conducted our research in a safe and responsible way. As such, again, we decided to speak with members of GMAC, which is the leading body advising the biosafety of engineered organisms. From our exchange, we understood that the IBC, established under the National Institute of Health (NIH) guidelines, reviews research experimentations across multiple institutions in Singapore. Our laboratories, the BioMarkerSpace at E6 and SynCTI at CELS is approved by the IBC and is certified for BSC1 and BSC2. Most importantly, we ensured that our experimentation protocols strictly comply to the NIH guidelines.

These various interviews helped us understand the safety and regulatory concepts of our project. They enabled us to make better decisions on the experiments to conduct, and helped to shape our project towards safer and easier execution.