Team:ICJFLS/Human Practices
Human practice
1. Investigation of the use of straws
1.1 The straws used in the market
According to the requirements of China's plastic restriction ban, non-degradable disposable plastic straws is prohibited to use in the catering industry from January 2020. We would like to know about the use of straws in the market. Therefore, we investigated the use of disposable straws. We found that there are mainly five kinds of straws used in the market: starch straws, paper straws, polylactic acid (PLA) straws, wheat straw straws and plastic straws (Fig.1). Their prices are ¥1.69, 0.16, 0.1, 0.09 and 0.06 yuan (Table 1), respectively. Of them, starch straw is the most expensive. We are curious about the performance of these straws, and then bought some straws and tested them.
Fig. 1. The five kinds of straws used in the market.
1.2 Test for toughness and hot water resistance of straws
We tested the toughness and hot water resistance of five kinds of straws commonly used in the market. They are starch straws, PLA straws, paper straws, wheat straw straws and plastic straws. When testing toughness, we designed two groups of experiments, one is random bending and the other is fixed-point bending. The experimental method of random bending is to bend the non-repeated points on the straw for 50 times to see the overall toughness of the straw. After knowing the average toughness of the straw, we tested the maximum toughness of the straw, that is, only one part of the straw was bent for 50 times, which is the fixed-point bending experiment. Then we conducted a hot water resistant experiment. The experimental method was to conduct a constant temperature water bath of 100 ℃ for 15 minutes for five kinds of straws.
1.2.1. Toughness test
1.2.1.1. Random bending
A）Experimental method: Randomly select the non-repeated point on the straw and bend it for 50 times, EXCEPT starch straw.
B）The bending resistences of the five kinds of straws were shown in Fig. 2.
Fig.2. The bending resistence of the five kinds of straws.
C）Experimental results:
We found that the wheat straw straw, paper straw and PLA straw had obvious cracks, plastic straw had not, and starch straw broke down every time.
1.2.1.2. Fixed point bending
A）Experimental method: select a part of the straw and bend it 50 times
B）The broken resistences of the five kinds of straws were shown in Fig. 3.
Fig.3. The broken resistence of the five kinds of straws.
C）Experimental results:
We found that the paper straw, plastic straw and PLA straw are not broken for 50 times, starch straws is broken for 1 time, and the wheat straw straws is broken for 4 times.
1.2.2. Hot water resistance test
1.2.2.1. Constant temperature boiling
A）Experimental method: Cook in 100 ℃ water for 15 minutes
B）The hot water resistences of the five kinds of straws were shown in Fig. 4.
Fig.4. The hot water resistence of the five kinds of straws.
C）Experimental results:
The PLA straw and paper straws are obviously deformed, and the wheat straw straws, wheat straw straw, starch straws and plastic straw are not deformed.
1.2.3. summary for the experiments
Through comparative analysis, PLA straw and paper straw deform under hot water conditions, and starch straw is easier to broken compared with wheat straw straw. The plastic straw has better characteristic, however, it is harmful of environment. These give us great suggestions to avoid adverse situations when preparing our new type straw.
2. Survey on consumer preference for straw use
In order to understand people's preferences for various straws and facilitate our project design, we designed a questionnaire. The question is, what kind of straws do you like to use? Why? The survey results show that 40.56% of people like starch straw best, and only 15.17% use paper straw (Fig.5).
Fig.5. People's preferences for various straws
Most people responded that the starch straw has the advantages of complete degradation, green composting, green environmental protection and no pollution. It is suitable for cold and hot drinks. But the price is high. People don't like paper straws because the straw cracks when using halfway, and have to need 2-3 straws each time. The paper straw will soon be soaked and softened, which may affect the drinking experience. The disadvantage of PLA straw is that it is not heat-resistant and can only be decomposed under specific environmental conditions and composting facilities. Wheat straw straw is not strong enough - you may need more. Plastic straw causes serious environmental pollution.
Since people like starch straw, how can we reduce the price of starch straw? Therefore, we consulted the relevant literature.
3. Literature review of starch straw
Starch mainly comes from grain crops, which is not conducive to saving food. Since people in many countries and regions in the world are hungry, saving food is of great significance. Starch contains amylose and amylopectin. The main component of starch straw is amylose, not amylopectin. The procedure of extracting amylose from starch is complex. Moreover, several organic compounds, such as nitro alkanes, thymol, t-butyl alcohol, and dimethyl sulfoxide, are involved to form a precipitatable complex with amylose during the separation of starch. These treatments not only have the potential risk to healthy, but also are costly and environmentally unfriendly, with thermo- or chemical reactions.
What are the ways to solve the source of amylose? synthetic biology?
We thought of cellulose synthesis of our 2020 iGEM project, and interestingly, cellulose is as a support material of straw. So, we got the idea on biosynthesis of amylose in bacteria, the most important component of starch for making straw. Amylose has good gel strength, low water holding capacity and poor water absorption and can form a film with good plasticity, which features are suit for making straw. We are very excited that we will solve the two main components of the starch straw using synthetic biology method. We decided to carry out this project.
Integrated Human Practices
1.Visiting factory of straw production
After some human practice activities, including the market survey about the plastic restriction ban, visiting customers, and the performance test of different straws, our team decided to develop straws using amylose which is synthesized in bacteria. Then we visited Huiyuan Food and Beverage Co. LTD in Zibo, Shandong province, which produces plastic straws.
Why did we visit the factory producing plastic straw?
Why don't they produce paper straws or starch straws? Why are plastic straws still produced under the plastic restriction ban? It is not friendly to environment. With these questions, we visited Huiyuan factory.
2.The production procedure of plastic straw
By listening to the explanation of the leader of this factory, we knew the procedure of producing plastic straws. There are five steps to make plastic straws. The first step is to mix and heat the polypropylene resin and color master batch at 220 Celsius degrees so that they melt at high temperature, and then sterilized the raw material for the first time. The second step is extrusion forming and cool them down. The third step is to cut and do micro bending. The fourth step is to sterilize the straws with ultraviolet light. The fifth step is to pack the plastic straws with packaging film.
What impact on our project?
By understanding the production process of straw, we know that there is a high temperature step, so we don’t need to worry about the amylose straw contaminated by E. coli, which can relieve people's fear of bacterial pollution in the amylose synthesis. This information will greatly promote the realization of our project.
3.Thinking about the alternative of plastic straw
Due to the plastic restriction ban, the leader talked about their plan for the transformation product. As we know, it is raw material of straws that we really care about. The main component of their products are polypropylene and color master batch. However, both of them are non-degradable. The reason why the factory still produce plastic straws is that the materials are relatively inexpensive, compared with paper straw and starch straw, which are relatively less fragile compared with straws (made by straw). Each plastic straw only costs a penny. However, each paper straw cost 4 pennies, and starch straws cost even more.
By conversation with the leader, we know that the cost is the most important factor on transforming products in enterprise operation. Next step, they plan to transform to the paper straw production although it has some defects. The starch straw is difficult to implement because of its high cost.
At present, the material of starch straw on the market mainly come from crops. That’s why its cost is high. And the starch extraction from crops is complicated. As we know from the literatures (please refer the project description of our project), the amylose of the starch is more suitable for straw production because of its properties.
However, there is no technology could purify amylose from starch or from crops, which indicated that our project is of great significance. At the same time, our project that using the E.coli to synthesize amylose could decrease significantly the cost of straw.
In addition, they told us about the lack of technology to produce environment friendly straws, which is one of the reasons why they maintain the production of plastic straws at present. Another reason is that according to the requirement of restriction plastic ban in China, the use of non-degradable disposable plastic straw is prohibited only on the catering industry. This is why they continue to produce plastic straws. However, it is imperative to transform to the products of degradable and environment friendly straw in the coming years.
Therefore, cost and technology are important bottlenecks limiting the development of enterprises. The whole society should help enterprises realize cost and technological innovation from different angles, such as our project. So we introduced our project to them, and they showed very interested in our project. They look forward to keeping in touch with us, and hope to cooperate in the production of amylose straws in the future.
By understanding the production process of straws and communication with leader, we had known thoroughly that:
1. The biggest barrier of producing environment friendly straws is high cost.
2. Cost reduction and technological innovation are important prerequisites for the production of environment friendly straws.
3. The high-temperature heating in the process of producing straw solves the concern caused by amylose synthesized from bacteria in our project.
Conclusion 1:
Visiting the factory confirmed that our project could develop a new technology to help factory transform other low cost and environment friendly products, such as bacterial amylose straw.
Next work we need to understand how do the public accept the bacterial amylose straw, and what do they have expectation for the new straw.
4.Survey of the acceptance and expectation for the amylose straw
We interviewed some students and random passers-by about the bacterial amylose straw. The interview questions were mainly about the innovation of straws. For example, what new features with the straw would you like when you drink beverage or milk tea? Have you ever heard of amylose straw? Would you accept a straw made of bacterial amylose and cellulose? And so on.
we summarized the results of the questions answered by respondents as follows:
The first question is that "what feature with the new straw do you want to have?" The statistical result showed that 80.73% of respondents chose the feature of no peculiar taste or smell; 75.48% of them also chose the feature of no broken; there is also 74.38% of them regarded the ability of biodegradable as an important feature; 45.52% of them would have no additives. 23.17% of them would have more colorful straw.
Fig. The features of amylose straws
From the answers of this question, we know that our product amylose straw need to meet these features, like biodegradable, no broken, no peculiar taste or smell, no additives, and less colorful, which make our project close to perfect.
The second question is that“Have you ever heard of amylose straw?" We can see from the result that 92.32% of respondents never heard of amylose straw, indicating that it is really a new material which have a wide potential application. We still need to do some more education.
Fig. The popularity of amylose straws
The third question is that "Will you accept the amylose produced from bacteria to make straw?" From the result we can see that although most respondents never heard of the amylose produced from bacteria to make straw, 53.89% respondents would like to accept the straw made from bacterial production; 42.67% of them want consideration; only 3.44% of people can't accept it, who are concerned hygiene.
Fig. The attitudes toward amylose straws
We took more attention on 42.67% of them who are hesitant to accept the amylose straw, therefore we did some publicity for the public.
Conclusion 2:
Survey work helped us to modify our project, supplement some education and communication work with the public, which make our bacterial amylose straw achieving more acceptable by the public.