Visiting the Macau Urban Farm

In March, we visited the Macau Urban Farm to know more about the current situation of hydroponics in Macau. Macau Urban Farm aims to develop and demonstrate high-quality and safe hydroponic farming. Their growing system creates an excellent environment for local organic food for Macau residents. During our visit, we understood the principles of hydroponics and the effects of various environmental factors including temperature, light, and nutrients on hydroponic plants, which has allowed us to have a better understanding of hydroponics.

Through this visit, we learnt about the precautions of planting, and we were provided with useful tips from the experts of Macau Urban Farm.

We learned when there is not enough oxygen, the roots of the plant will respire anaerobically and the plant will produce alcohols, which will then lead to corrosion of the plant, and it will eventually wither. To prevent this from happening, we were told that some potassium permanganate could be added to the water.

For better plant growth and yield, they suggested we maintain the temperature at 25°C and the pH value at around 6.5. Since we are planning to set up our system indoors, they told us we do not need to worry about the pest problem.

Having known the factors above, our first idea was that pH value can be a great factor in the results of the harvest, which gave us a new direction for our experiments. Our ultimate goal was to find ways to make hydroponic plants have a better harvest, and we believe that can be done by maintaining the pH value at an optimal level. To test our hypothesis, we designed and then started our experiments.

Assembly Talk

We had a presentation with Secondary 3 students in April through an assembly talk. In the talk, we introduced what iGEM is and provided some background information on synthetic biology. Additionally, we mentioned some critical environmental issues such as climate change and extreme weather, which we aimed to solve. We explained the rationale of our project, and the majority of our students were interested in it. Besides the experiment part, we also covered the hardware, modelling, and outreach parts.

We had a Q&A session when our presentation was over. Most of the questions involved global issues and iGEM. All the students responded positively. They raised their hands eager to answer questions. We prepared products designed by our teammates as gifts, and the students really enjoyed them.

Our team has been set up for 4 years, and we have been actively promoting iGEM and the concept of using synthetic biology to solve local issues. From this assembly talk, we can see that environmental topics are interesting to students of our school. Moreover, most students from our community are getting more familiar with iGEM and many of them are eager to join us. We hope to continue our promotion in the future and educate more people from our community to share their insights on global issues around the world.

Visit and presentation at Wynn Macau

Wynn Macau has been providing us with strong support over the past few years. On the 15th of September, we visited Wynn Palace and had a meeting with the Wynn Team for further advice on our project as well as to learn about what large cooperations like Wynn consider while purchasing food products.

At our meeting, we presented our 2022 iGEM project and ​​explained the background of our improvements to the current hydroponic system. We showed our experiment rationale, along with some of the results to them

While experts at the Wynn Team acknowledged our ideas, they also expressed some concerns about our project. Ms. Ruby O, the chairperson of SFEH (Society of Food & Environmental Health (Macau)), questioned the sustainability of our proposed implementation kit. The original kit was made of non-biodegradable acrylic, which would likely remain in the Earth's crust for a long period and even pollute the environment. The Wynn team suggested we use reuse old materials or use biodegradable materials for the whole kit, including the packaging, to take a step further in promoting sustainable consumption. Thus, through research, we have figured out an efficient way to solve this problem, which is to create new acrylic sheets with old or scrap acrylic plastic.

The experts also asked whether the E. coli used in our project is suitable for consumption. We showed our research on the food safety regulations of microorganisms in Macau and explained that the E. coli would only be on the surface of the produce, which can be removed with thorough washing, and thoroughly exterminated through cooking. However, as the public has a bad perception of E. coli, we were suggested to replace it with yeast in the future or add UV light devices in our to kit to deactivate it.

When asked about food procurement, Wynn explained that the major factors they would consider were the foods' hygiene and quality. They stated that a collaboration would be possible if our project can be implemented on a large scale and our produce is completely proven to be safe to eat.

At the end of our meeting, we also presented a painting of Wynn from our graphic designer Gloria as a present to Wynn. We would like to once again thank Wynn hotel for their generous support over the years and are looking for more opportunities to cooperate in the future.

1st Climate Change in Macau Conference

On 25th September, our team leader Gina Liu was invited as a speaker at the 1st Climate Change in Macau Conference held by the Greenfriends Macau in the Centro De Cultura e Artes Performativas Cardeal Newman De Macau (CCCN Macau).

Gina gave her presentation on microplastic research and introduced how the iGEM project can help with dealing with climate change. She shared how microplastic pollution is being more serious, and how Antarctic circumferent brings plastics to Antarctica. Gina then shared our 2022 iGEM project by introducing climate change's current impact on food supply, and how synthetic biology offers a new way of solving food supply problems.

During the conference, many audiences exchanged their ideas on environmental protection with her and shed valuable insights on our project.

The meeting can be reviewed on Facebook with the following link: https://fb.watch/fM81ADXnlg/

Visit to IFTM

To study other branches of water-based agriculture in Macau, we visited Macao Institute for Tourism Studies (IFTM) to check out the hydroponics and aquaponics system there on 27th September this year.

The institute has built a rooftop garden, which can reduce the conduction of heat to the building. There are many kinds of plants growing in the garden, including mango and papaya trees, mint, and other herbs. The Michelin-recommended restaurant of IFTM then makes use of these edible plants to create various Macanese dishes.

There are two different hydroponic systems at IFTM, in one of which rock pieces are added, while the soil is added to the other. The tubes containing nutrient solution are made of PVC that fit the Certified Agricultural Standards. Additionally, they use water tanks to recycle the water circulating in the system, and mint is planted to repel harmful insects.

The aquaponics system of IFTM is made up of two parts: the fish tank and the planting area. They utilise the ammonia produced by the fish to facilitate better plant growth using the nitrate transferred from it. They would also add mycorrhiza to speed up the rate of nitrogen fixation.

While explaining the distinguishment of health conditions of plants, the experts in charge of the systems told us we can check with leaf colours. For example, if the leaf is yellowish, it can be deduced the plant lacks iron ions, and iron-rich nutrients can be added to the plant. In terms of pathogen control, they stated that outdoor hydroponics has a higher possibility to be damaged by pests. To deal with this problem, we were suggested to plant garlic or herbs, which have a stronger aroma that pests usually dislike.

The professors from USJ joined our visit at IFTM and shared their experiences on aquaponics and hydroponics.

Enhance the Constructs' Design after Meeting with the Faculty of Health Sciences of University of Macau

At the very beginning, we designed our three constructs: glsA, genetically pH shooting system (glsA + ldhA) and sfGFP(K2762014) using a pET11a vector with a T7 promoter system. We had accomplished experiments on validating the pH maintenance with the three pET11a constructs, and also measured OD 600 and fluorescence to demonstrate the survival of the transformed E.coli. However, our results (particularly genetic pH shooting system) were not very significant compared to the control group. We then invited Samson, the technician of our advisor’s lab at the University of Macau to verify the constructs. He told us that our pET11a system has a big logical mistake. Since we used independent promoters, asr promoter for glsA (acid shooting circuit) and sfGFP (acid fluorescent bioindicator); P-atp2 promoter for ldhA (base shooting circuit), the efficiency of our plasmids will be lower than average since we do not use IPTG induction for our system. To improve our plasmids, he taught us how to put our constructs into a pSB1C3 system which can contain two sets of bio-bricks, and is ideal for our two systems.

Meeting with Professor Lam from CUHK

In August, we invited Professor Lam Hon Ming to share his recent agricultural sustainability and biotechnology research and give his insight on our 2022 iGEM project. Professor Lam is a professor at the School of Life Science of CUHK and is well-known for his excellent biological projects: soybean species selection and breeding, and the genetic information to preserve local heirloom rice variation in Hong Kong. We were extremely pleased to learn more about the research he has been working on, we received useful advice for our 2022 iGEM project.

During the discussion, Professor Lam shared his knowledge on practical operations of hydroponic systems, such as the differences between open and closed systems, as well as the intricate process of plant germination. In terms of growing plants, Professor Lam imparted some skills to determine whether the plants are healthy or not. There are three main methods: The first method is visual inspection, which is determined by looking at the form (yellowing or firmness) of the leaves. The second method is PCR inspection, which can be used when it is unhealthy due to virus or egg infections. The third method is to use monitoring cameras to determine the health of the plants through observation.

In this meeting, we also introduced our project "Hormone Binding Domain & Genetic pH Shooting System" and the obstacles we had been facing to Professor Lam. We had found it difficult to control the water quality in our proposed kit. He recommended that we should change the design of our kit into an open system since it will be easier to control the nutrient quality in that way. Even though the E.coli we transformed with GFP was able to grow better in hydroponic water than in pure water, it is undeniable that E.coli needs a more suitable environment to express our target protein. Professor Lam reminded us that we would possibly need an enormous amount of E.coli to change the pH value of the water, which might not meet the requirement of food safety. To improve our system, we would redesign the system, and set up a tank for E. coli to grow in its best environment with LB medium. Then, when the program we set up detects low pH (using biosensors or physical sensors), the water can be diverted into the filtering system, hence adding E.coli to neutralise the pH level.

As our current solution, in which we apply E. coli to a hydroponic system to help plant growth, needs long validation process and might raise concerns of efficiency difficulties in application, Professor Lam suggested that we can try developing biosensors to detect the health of the plant or the quality of the cycling water. We have been testing the use of sfGFP, a fluorescent indicator of low pH conditions (pH 4). Therefore, we are now improving this indicator and applying this to regular hydroponic systems or our prototype home kit.

Visit and Presentation at IAM, Laboratory Division

On the 7th of September, we visited the laboratory division of the IAM. There we received support and encouragement from their scientists, and discussed our future direction and plans with them.

We asked them what regulations and indicators we need to consider. They told us that for the vegetables we are growing in our hydroponic system, the laboratory usually tests for the value of heavy metals and toxins. Referring to the Microbiological Guidelines for Instant Foods published by the Macau government[1], the indicators of microorganisms are not suitable for fresh vegetables and fruits, because typically there are many normal bacteria that are attached to the surface. In some rare cases, in which the vegetables are contaminated directly by STEC (Shinga toxin-producing E.coli)[2], they test the level of the microorganisms. However, an investigation[3] concludes that the BL21 strain of E.coli, which is the E.coli strain wuse for our system, is not pathogenic. Furthermore, most E.coli will be removed through the washing and cooking procedure. Yet, considering the stereotypes of E.coli in the public, we planned to use yeast as an alternative to transform our system into this more acceptable biological machine.

The experts of IAM showed us their laboratories where food safety tests are conducted. We learnt that there are many processes before the final results. We were very impressed with their professional methods and the safety regulations of microorganisms, which are very important to our project.

Reference

1. Municipal Affairs Bureau (IAM) of the Government of Macao Special Administrative Region (2015). Microbiological Guidelines for Ready-to-eat Food.
2. Centers for Disease Control and Prevention (2014). Questions and Answers of E. coli (Escherichia coli).
3. Chart H., Smith H.R., La Ragione R.M.,& Woodward MJ (2000). An investigation into the pathogenic properties of Escherichia coli strains BLR, BL21, DH5alpha and EQ1, Journal of Applied Microbiology. Surrey, SY: Society for Applied Microbiology, Wiley-Blackwell.