Genetic engineering for good: NUS team wins second spot in global competition with low-cost biopesticide

Singapore farms wrestle with the same challenge faced by farmers around the world: pest control. In the light of this challenge, a safe, organic and cost-efficient pesticide is vital to enable Singapore farms to bolster food security and contribute to hitting Singapore’s “30 by 30” goal – to produce 30 per cent of its nutritional needs locally by 2030.

The solution came from a 10-member interdisciplinary team from NUS, after six months of intensive research and innovation.

Called “PRYSM”, this low-cost biopesticide led the team to clinch the second spot at the 2021 International Genetically Engineered Machine (iGEM) – the best showing by a Singapore team to date. The annual synthetic biology competition drew 350 teams from around the world this year.

Serving a local need 

The NUS team was motivated to solve a local problem which one member, Year 4 NUS Life Sciences undergraduate Chew Chin Wei, saw first-hand while interning at Singrow, a homegrown agritechnology start-up.

“Singrow lost a significant portion of its yield due to pest problems,” he said. “If our team can solve the pest problem, farms in Singapore can contribute to the ‘30 by 30’ plan.” 

The team started by speaking to eight local farms, from vertical to hydroponic farms. “We wanted our solution to be very versatile and help all sorts of farms,” explained Weng Yi Dou, a second-year undergraduate at NUS Computational Biology

They discovered that outdoor farms wanted greener, more organic pesticides as they tended to overuse synthetic pesticides. Meanwhile, organic farms were helpless against pest problems as they could not use synthetic pesticides.

“Farms don't want to use synthetic pesticides but when they didn’t use them, their yield is significantly reduced,” said Chin Wei. “That is an issue because farmers need high yields.”

The alternative of using organic pesticides is also unsustainable due to the high costs, he added. 

A gap to fill

Given the dilemma, the team did extensive research on existing biopesticides, which they found often come from utilising large amounts of animal or plant matter. But rearing these animals or crops in large numbers is not feasible in land-scarce Singapore. 

Undeterred, they explored other means and struck gold after speaking to a local biomanufacturing start-up. They found that the human immune protein, human beta defensin, can be used to kill bacteria, which means it can effectively also be used as a biopesticide. Better yet, it is safe for human consumption.

“The pest we want to eliminate is a fungus,” explained Chin Wei. “When many human beta defensin molecules enter the fungus’ cell membranes, the membranes will become unstable and burst. The fungus’ cells will thus be destroyed.” 

The team used synthetic biology techniques to engineer baker’s yeast, a common genetic engineering organism, to produce the protein under certain conditions, similar to how insulin is produced from engineered bacteria. 

Wallet-friendly and efficient 

Typically, triggering baker’s yeast to produce certain compounds requires the addition of costly chemicals. This was not viable for the team, which wanted a cost-efficient solution.

Instead, they used optogenetics – a method whereby cell activity is controlled by light – to eliminate the need for chemicals. “When red light is shone on the yeast, the yeast will produce human beta defensin,” said Chin Wei. 

To carry out this process, the team produced a small-scale, open-sourced bioreactor with LEDs to culture the yeast. The bioreactor was 3D-printed and costs less than S$1,000 – a fraction of the S$100,000 price tag for a standard bioreactor in the market.

It was a success. The team managed to culture 100ml of yeast with their bioreactor for the competition, proof that their concept worked. Finally, the team purified the biopesticide with blue light to separate the yeast from the human beta defensin proteins.

Strength in diversity for a surprise win

While their biopesticide was a success, the team was still surprised that they won second place.

Associate Professor Poh Chueh Loo, the team’s mentor from NUS Biomedical Engineering, was proud of the team. “NUS has been participating in iGEM since 2017, and this is the best result that we have achieved,” he enthused. “It is also the first time that a Singaporean team has reached the top two!”

While the biopesticide is still in the early stages of development, Assoc Prof Poh believes the team is onto something. “The project offers a potential new solution to the production of biopesticides for the agricultural industry in Singapore,” he noted.

Team memberMajor and Year of Study
Chew Chin WeiY4 Life Sciences
Weng YidouY2 Computational Biology
Chen YilinY3 Data Science and Analytics
Andrew AureliusGraduated Biomedical Engineering
Truong Dong HungY4 Biomedical Engineering
Bharathkumar SriramY2 Biomedical Engineering
Tania NairY4 Biomedical Engineering
Linus Tan Yu HanY4 Life Sciences
Vedant SandhuY4 Pharmaceutical Sciences
Leong Kay MeiY4 Applied Maths

Chen Yilin, a third year NUS Data Science and Analytics undergraduate, credits the success to the team’s diversity. The team members come from different majors: Biomedical Engineering, Pharmaceutical Science, Data Science and Analytics, Life Sciences, Applied Mathematics, and Computational Biology.

The scope was complex, and the project ambitious. It involved not just engineering of micro-organisms and building hardware, but also developing computational models, interviewing stakeholders, outreach, the design of web pages, and video presentations.

“We worked very cohesively, and everyone played to their strengths. We all have valuable takeaways from this holistic and multidisciplinary experience,” said Yilin.

Indeed, strength lies in diversity, said team member Andrew Aurelius, an NUS Biomedical Engineering graduate. “We can’t all be scientists running experiments the whole day. You need different skillsets that complement each other. It is about supporting each other,” he said.

For Yi Dou, who has always thought of herself as a hard sciences person, the experience even helped her uncover her love for journalism – a field that she had never considered prior to the competition.

“After interacting with people and understanding their problems through iGEM, I started to enjoy the dynamics between people,” she said. Today, she is interning at Lianhe Zaobao, Singapore’s flagship Chinese-language daily. “I found my passion.”

The team expressed their thanks for the support from NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI) - the leading synthetic biology research centre in Singapore - and the BioMakerSpace @ Engineering, as well as the past NUS iGEMers.

Read more about the team’s iGEM project at their website.