1.Background and Significance

The plastic straw is one of the most commonly used tableware in the catering industry, especially in beverage stores. The data showed that the annual use of plastic straws in China was about 46 billion in 2019, and about 500 million plastic straws were discarded every day in the United States, and about 8.5 billion plastic straws every year were discarded in the United Kingdom. The plastic degradation time may be as long as 500 years. These plastic straws have caused serious harm to the ecological environment and animals. One straw into the turtle's nasal cavity almost killed the turtle.

As people pay more and more attention to environmental protection, the plastic ban storm quickly swept the world. In 2020, the "most stringent plastic restriction ban" was issued in China. Which means that the use of non-degradable disposable plastic straw would be prohibited in China's catering industry. The British government announced earlier this year that it plans to push for a new "plastic ban" in England. The European Commission proposed a "plastic restriction" plan in May, recommending banning disposable plastic products like plastic straws.

Under the background of plastic restriction ban and the increasing consciousness of environmental protection, businesses mainly chose the paper straw and poly lactic acid (PLA) straw. However, the paper straw has some defects such as easy broken, low strength, easy softening, and peculiar smell, etc. PLA straw is not heat-resistant and UV resistant, short storage period, and its price is relatively expensive. So few shops use PLA straw. It is really a very intractable problem for businesses and customers. Finding a better alternative is the most important thing.

2. Proposed Implementation

This year, our project tried to solve this problem. We are exploring the synthesis of amylose in bacteria to make straw instead of paper straw and PLA straw. Bacterial amylose is a kind of high value-added product with great potential application value. People have started to explore the application of amylose in food, package/medical materials, biodegradable plastics, etc., but no one studied the use of amylose synthesized in Bacteria to make straw. This is the novel of our project.

2.1 Who will use

Straws are widely used in the world. The annual amount of used plastic straws was about 46 billion in China, 180 billion in the United States, 8.5 billion in the United Kingdom.

At present, disposable straws, lunch boxes and water cups are mostly made of plastic, which is difficult to degrade and pollutes the environment. Under the requirements of restriction plastic ban and the state vigorously advocating environmental protection, the industry transformation is inevitable. Disposable product made of amylose and cellulose has higher social value, and is more beautiful than plastic disposable product. It not only meets the needs of modern people's fashion consumption, but also make environmental protection and low energy consumption. Amylose used for making disposable product mostly comes from food crops. However, some countries and regions in the world are still in hunger and poverty. We have successfully synthesized amylose in E. coli for making disposable straw, which is conducive to saving food and to environmental protection, and also meets the requirements of sustainable development.

Amylose straws made from bacterial product are not only biodegradable, no taste or smell, no broken, but also save food, inexpensive, and will be welcomed warmly by consumers. Our survey showed that most people can fully accept it, and a large number of people are willing to accept it through necessary propaganda and education. As long as a large number of people accept it, the new type of amylose straws will be booming for producing and selling, forming a virtuous circle. It will benefit the world, business and ourselves.

2.2 How to implement

The production equipment of disposable straw is available for improvement in the existing complete set of equipment. A large number of transformed E. coli synthesizing amylose are cultured, broken and sterilized for use. In addition, a large number of transformed E. coli (got from the project of our iGEM team last year) synthesizing cellulose are also cultured, cellulose is collected from the surface of medium and sterilized. The E. coli expressing amylose and cellulose and other necessary additives are mixed in a certain proportion, mixed with water to make raw materials, and then made into the shape of straw by certain forming technology, Special drying process is adopted to ensure its hardness and flexibility. After disinfection and packaging, it can be ready for use. A series of complete production lines of making amylose straw include main material extraction, additives proportioning and mixing with water, hot pressing forming, drying, quality inspection, disinfection, packaging and warehousing. We have contacted the straw manufacturer, who is responsible for helping us to test the properties, compared with the existing straw standard.

Next, we will collaborate with a manufacturer of straw. At the beginning of our project, we visited the workshop of straw manufacturers to learn about the workflow and relevant requirements of straw production. At the same time, we introduced our project to them. They were very interested. They thought it was a very promising project, and expressed their willingness to cooperate with us. That gave us a lot of encouragement!

3. The potential safety

The bacterial amylose and cellulose we used are organic compounds synthesized by E. coli. Therefore, it may be contaminated with E. coli during the synthesis process. So the bacterial amylose and cellulose obtained in fermentation broth needs extraction and sterilization process. In addition, amylose and cellulose may be nutrient substances for some microorganisms, so the bacterial amylose and cellulose straws may be contaminated with microorganisms in moist conditions. These microbes may degrade amylose and cellulose to provide energy for themselves. So the preservatives will be used to keep from microbes. It’s better to remind the business to always keep straw dry.

4. Challenges

Although our project is very promising, we still meet some challenges. The yield of bacterial amylose produced by E. coli are very low now. In order to increase the yield, all the conditions of fermentation need to be optimized. Experimental data on extraction and preservation of bacterial amylose are not available yet. There is still much work to be done in the future. The questionnaire also showed that some people hesitate to accept the straws made of bacterial amylose. We still need to do more propaganda in order to get more people's recognition and acceptance.

5. Inestimable economic and social value

When our project is completed, and the bacterial amylose is used for the production of straw, its economic value and social value are inestimable.

First, using E. coli to synthesize amylose would greatly reduce the cost of straws. Even more, we could also use the crops waste, such as corn stalks, as an energy source for bacteria fermentation, which would be even cheaper. Now some countries and regions in the world are still in hunger and poverty. Billions and billions disposable straws made from amylose synthesized in E. coli are conducive to saving food, which is benefit the world and ourselves.

In addition, straws are widely used by people all over the world now, and millions of straws are discarded every day. It has been reported that discarded straws have caused great environmental pollution to humans (please refer to our project description). It is expected that our project can be realized and the bacterial amylose straws can be put into the real world. Bacterial amylose straw is a biodegradable product and can be used for other purposes after degradation, such as serving as fertilizer. This is a great benefit to the protection of human environment and the improvement of energy efficiency.