Presented by Team JNFLS 2020
Guangyi Lu, Guangzhong Zhang, Hanqin Yang, Jiaying Wu, Shanglin Song, Shufan Li, Xiaotong Lu, Yinuo Sha, Yinuo Zang. Jinan Foreign Language School, China, 250108
Abstract
Bacterial cellulose applied for making mask. Now there are more than 200 million non-biodegradable masks abandoned to the environment every day due to the pandemic novel coronavirus. We are trying to make a new antibacterial and color-changing mask using bacterial cellulose (BC) which is biodegradable. And its translucency is very benefit for facial recognition without removing the mask. Due to the limitation of BC production at present, we cloned the genes involved in the BC synthesis from acetobacter xylinus, and transferred them into the E. coli for the purpose of industrial production.
Team:JNFLS/Poster
Poster: JNFLS
Bacterial cellulose applied for making mask
Introduction
To prevent the spread of novel coronavirus, more and more people wear masks in public. So millions of disposable masks which are not biodegradable are discarded to the environment. It is hazard to the environment.
We are trying to make a new type of mask which is biodegradable, using bacterial cellulose (BC). This type of mask is antibacterial and color-changing because some special matters are added when BC is synthesized. And this type of mask is translucency because of its natural feature, which is very benefit for facial recognition without removing the mask.
Due to the limitation of BC production at present, we cloned the genes involved in the BC synthesis from acetobacter xylinus, and transferred them into the E. coli for the purpose of industrial production.
We are trying to make a new type of mask which is biodegradable, using bacterial cellulose (BC). This type of mask is antibacterial and color-changing because some special matters are added when BC is synthesized. And this type of mask is translucency because of its natural feature, which is very benefit for facial recognition without removing the mask.
Due to the limitation of BC production at present, we cloned the genes involved in the BC synthesis from acetobacter xylinus, and transferred them into the E. coli for the purpose of industrial production.
Inspiration
In order to prevent the pandemic novel coronavirus spreading around the world, people need wearing masks in public, so millions of masks are discarded every day now. You can see the disposable masks everywhere, whether on the land or on the sea floor. A new type of pollution is emerging, derived from the novel coronavirus. See these pictures.
The worse matter is that disposable masks are not biodegradable because its main component is polypropylene, which needs 200 to 1000 years to be decomposed in a natural environment.
So, how to combat novel coronavirus and reduce environmental hazards at the same time becomes the new research field. Our project aimed to make the masks using bacterial cellulose which is biodegradable, instead of polypropylene.
The worse matter is that disposable masks are not biodegradable because its main component is polypropylene, which needs 200 to 1000 years to be decomposed in a natural environment.
So, how to combat novel coronavirus and reduce environmental hazards at the same time becomes the new research field. Our project aimed to make the masks using bacterial cellulose which is biodegradable, instead of polypropylene.
Problems
1. In nature, there are many bacteria that can produce cellulose, the most common is acetobacter xylinus. However, the ability of synthesizing bacterial cellulose of acetobacter xylinus tends to decline during the preservation of strain.
2. Low yield and high cost are still a bottleneck for the large-scale production and industrialization of bacterial cellulose.
2. Low yield and high cost are still a bottleneck for the large-scale production and industrialization of bacterial cellulose.
Design
We cloned the genes related to cellulose synthesis in the acetobacter xylinus, and transfer them to the engineered E. coli, hoping to be able to produce bacterial cellulose using E. coli, realizing industrial production of BC.
There are 4 enzymes are involved in the synthesis in acetobacter xylinus, catalyzing the following 4 reactions.
In order to increase the practicality of bacterial cellulose, spirooxazine, a photosensitive compound, is added to the culture of E. coli, making the synthetic bacterial cellulose is color changing. In addition, by adding chitosan to the fermentation medium, the production of chitosan/cellulose composite material synthesized in situ has antibacterial properties.
In order to increase the practicality of bacterial cellulose, spirooxazine, a photosensitive compound, is added to the culture of E. coli, making the synthetic bacterial cellulose is color changing. In addition, by adding chitosan to the fermentation medium, the production of chitosan/cellulose composite material synthesized in situ has antibacterial properties.
Engineering
The 3D mask was printed. It will be used as a model to acquire the bacterial cellulose with fixed shape when we put it into the culture medium of the E. coli.
Results
To realize the production of bacterial cellulose in E. coli, we cloned 7 genes related to the synthesis of BC from acetobacter xylinus. Some genes were amplified using method of PCR, and one of them was synthesized directly. In order to insert these genes into the bi-expressing vector pETDuet-1, we connect some genes together to form polycistron using the overlapping PCR method.
Also, we cultured the acetobacter xylinus to optimize some conditions for higher BC production yield. And the results are showed in the following figures.
And the optimization experiment results indicated that 30°C, pH6.8, fermentation 7 days, 10% inoculum size, and glucose serving as the carbon source are the greatest culture conditions for high BC production yield in acetobacter xylinus. These optimized conditions can be referred for the following production of BC in E. coli.
Also, we cultured the acetobacter xylinus to optimize some conditions for higher BC production yield. And the results are showed in the following figures.
And the optimization experiment results indicated that 30°C, pH6.8, fermentation 7 days, 10% inoculum size, and glucose serving as the carbon source are the greatest culture conditions for high BC production yield in acetobacter xylinus. These optimized conditions can be referred for the following production of BC in E. coli.
Modelling
To achieve the optimal composition of culture conditions, we made a model. The yield of BC is related to many culture conditions. These factors also influence each other. In order to acquire the maximum economic result, we used mathematical models to find the optimal inoculation quantity and the fermentation time, to acquire the maximum yield of BC. It is suggested from the modelling result that 7% initial inoculation amount is the best one, because it is not only effective but also economy.
Human Practice
In order to learn about the production process and safety requirement of masks， we visited a company which sells sanitary products, including masks and tissue.
After visiting, we made a conclusion: 1.The main component of masks is polypropylene which is not biodegradable; 2.The principle of sterility is very important for the masks production.
To make our project more reliable, we designed and handout a questionnaire about the mask. We also chose some important questions to analyze.
As a result, we made a video for appealing the public to wear mask. More important, we held the club activities to preach the iGEM competition to grade 10 students.
we also had an online interview with actual doctor Since doctors often wear masks, we want to adopt some advices about the use of masks from doctors. In addition to the doctors, we also interviewed strangers in public about the innovation of masks.
According to our human practice above, we modified our project. When we culture the E. coli for production of bacterial cellulose, the spirooxazine is added to the medium, which make the bacterial cellulose can change color under the light condition. And, the chitosan is also added to the medium, making the cellulose with antibacterial property.
After visiting, we made a conclusion: 1.The main component of masks is polypropylene which is not biodegradable; 2.The principle of sterility is very important for the masks production.
To make our project more reliable, we designed and handout a questionnaire about the mask. We also chose some important questions to analyze.
As a result, we made a video for appealing the public to wear mask. More important, we held the club activities to preach the iGEM competition to grade 10 students.
we also had an online interview with actual doctor Since doctors often wear masks, we want to adopt some advices about the use of masks from doctors. In addition to the doctors, we also interviewed strangers in public about the innovation of masks.
According to our human practice above, we modified our project. When we culture the E. coli for production of bacterial cellulose, the spirooxazine is added to the medium, which make the bacterial cellulose can change color under the light condition. And, the chitosan is also added to the medium, making the cellulose with antibacterial property.
Innovation and Reference
Our project has 3 points of innovation.
1. We did not find research that using BC to produce masks in the published papers.
2. The bacterial cellulose mask has the color changing and antibacterial properties.
3. Our bacterial cellulose masks are translucent, enabling face recognition without removing the mask.
[References]:
1.Selestina Gorgieva and Janja Trˇcek. Bacterial Cellulose: Production, Modification and Perspectives in Biomedical Applications. Nanomaterials, 2019, 9: 1352-1371.
2. Thanaporn Amnuaikit, Toon Chusuit, and Panithi Raknam, et al. Effects of a cellulose mask synthesized by a bacterium on facial skin characteristics and user satisfaction. Medical Devices: Evidence and Research, 2011, 4: 77-80.
1. We did not find research that using BC to produce masks in the published papers.
2. The bacterial cellulose mask has the color changing and antibacterial properties.
3. Our bacterial cellulose masks are translucent, enabling face recognition without removing the mask.
[References]:
1.Selestina Gorgieva and Janja Trˇcek. Bacterial Cellulose: Production, Modification and Perspectives in Biomedical Applications. Nanomaterials, 2019, 9: 1352-1371.
2. Thanaporn Amnuaikit, Toon Chusuit, and Panithi Raknam, et al. Effects of a cellulose mask synthesized by a bacterium on facial skin characteristics and user satisfaction. Medical Devices: Evidence and Research, 2011, 4: 77-80.