Tstl Melanie C S Pta

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Concernant la présentation orale.

La durée est trop longue (6:30 mins au lieu de 5 mins!)

N'oublie pas de bien prononcer le morphème –ed : "performed", "obtained", "it can be concluded",…

"problematicatical" =} "problem-question"

Attention Ă  la prononciation de certains mots comme "finally", "purpose", "high"… et surtout des mots "transparents" comme "micro", "biodegradable", "nature", "degrade",…

Attention aussi Ă  la position des adjectifs, il faut les placer toujours avant les noms : "plastic manufactured" =} "manufactured plastic

Il faut bien prononcer les "s" Ă  la 3ème personne du singulier et après chaque mot au pluriel : "…number of questions….

Il y a des mots mal prononcés dans certaines phrases comme par exemple celle-ci : "Then the soil with the plastic bag no change but the ???? biodegradable made bag", ou "it can be concluded that degrade the facade???? make", ou celle-ci "The bag is a pure strain bacillus subtilis ??? aerobics.."

"For finish" =} "To finish…"

C'est assez bien présenté et ton texte est assez bien écrit.

The bioplactic


The history of plastic

Since 1950, global plastic production has steadily increased. It reached a record 320 million tonnes in 2015, equivalent to 10.1 tonnes per second, consuming about 8% of world oil production, as illustrated by the impressive count of the Planetoscope published in September 2018 on the Consoglobe website.

The consequences of this accumulation of plastic are dramatic. Plastic bags can block waterways and accentuate natural disasters. By clogging sewers and providing breeding grounds for mosquitoes and parasites, plastic bags can increase the transmission of vector-borne diseases such as malaria.

This accumulation is all the more worrying as the material takes centuries to disappear. In fact, most plastics are not biodegradable, they slowly break down into smaller fragments known as microplastics. When plastic decomposes, it is even more difficult to remove it from the oceans. Studies suggest that thousands of years are needed for plastic bags and polystyrene containers to decompose, contaminating soil and water during this time.

At a time when plastic is stifling nature and oceans and the world realizes that its recycling is not the solution, the alternative is bioplastics.

Unlike a traditional plastic made from fossil carbon, the bioplastic are made from the polymerization of plant cells. It can be made from whole plants, starch extracted from cereals (wheat or corn) or potatoes, starch-derived glucose or vegetable oil.

Background and problematic

Plastics have invaded our everyday world in areas as diverse as packaging, building, transportation, electrical and electronic equipment, furnishings and leisure. Global demand continues to grow. 5.000 billion plastic bags are consumed worldwide every year, or nearly 10 million per minute, according to the UN. Only 9% of the nine billion tons of plastic the world has ever produced has been recycled. A slightly larger share - 12% - was incinerated. The rest ended up in landfills, oceans, pipelines, where it would take thousands of years to completely decompose.

In recent years, rising oil prices have increased awareness of the limits of fossil resources and the desire for greater climate protection and sustainability. A particular category of this group of materials, in this case bioplastics, has attracted interest.
We are therefore faced with a number of questions which reflect as many hypotheses and imply the problematic of our present study:
"How would the use of bioplastic bags limit environmental pollution?"

To answer to the problematic, we performed eight manipulations. First, we manufactured a bioplastic film based on corn starch. Then we compared the resistance of the bioplastic bag with that of the plastic bags and manufactured. The aim is to see if there is a link between the resistance of the plastic and the time of its degradation. Then we composted. The goal was to see how different plastic bags degrade in nature. Then came the enzymology, which consists of identifying the bag that degrades in a short time and carrying out microbiological tests to demonstrate the characteristics of the bacterium Bacillus subtilis and its concentration. Finally, we carried out a small experiment with the Fehling liqueur to find a reducing sugar.

The objective of our work is to demonstrate that the bioplastic bag is the least polluting.
To complete our study, we will present the project as a whole in the first part. Namely the interest and the why of our study. The second part is devoted to one of the different manipulations carried out to answer our problem. With this in mind, eight protocols have been developed to compare the bioplastic bag with the other bags. The results of these experiments are described in Part Three.

One handling among the eight

The handling that I present is the third one that compost.

The purpose of this experiment is to see if a plastic bag is put into nature and to see its degradation. Also some bag, it has written that it is possible to put it in compost (biodegradable bag that of fruits and vegetables in supermarket: Oseo). So we made 16 different composts, 8 indoors at room temperature and 8 others outdoors with the weather ( winter temperature). In this experiment we used the bacterium Bacillus subtilis to see if with or without it changes some things to the plastic when it would be in nature.

- Composition :

Inside :

N°1 : 200g of compost
N°2 : 200g of compost + Bacillus subtilis
N°3 :200g of compost + 10cm2 of plastic bag
N°4 :200g of compost + 10cm2 of bioplastic bag biodégradable
N°5 :200g of compost + 10cm2 of plastic bag make
N°6 :200g of compost + 10cm2 of plastic bag + 10mL Bacillus subtilis
N°7 :200g of compost + 10cm2 of bioplastic bag + 10mL Bacillus subtilis
N°8 :200g of compost + 10cm2 of plastic bag make + 10mL Bacillus subtilis

outside :

N°9 : 200g of compost
N°10 : 200g of compost + Bacillus subtilis
N°11 :200g of compost + 10cm2 of plastic bag
N°12 :200g of compost + 10cm2 of bioplastic bag biodégradable
N°13 :200g of compost + 10cm2 of plastic bag make
N°14 :200g of compost + 10cm2 of plastic bag + 10mL Bacillus subtilis
N°15 :200g of compost + 10cm2 of bioplastic bag + 10mL Bacillus subtilis
N°16 :200g of compost + 10cm2 of plastic bag make + 10mL Bacillus subtilis
We left the compost for a month. At the end of this term we took back those that were outside and we had no difficulties, the winter temperatures with its bad weather were enough to feed the composts of what they needed to have a good compost.
While for the one inside there were some complications. A week after making the compost with or without the bacteria. Even with or without plastic, we were obliged twice a week to return at least 10mL of water to humidify the earth as it dried up very quickly when it was at an ambient temperature.  With its difficulties we have managed to have exploitable results.

The results obtained for the 8 handling

1/ We obtain a thick and colorful film that we can use for our handling and to form a plastic bag make.

2/ Note that the plastic bag and the plastic bag make have the same strength. While the biodegradable plastic bag has a lower resistance than the plastic bag and the plastic bag make. We can therefore conclude that there is no link with degradation, because the plastic that degrades the fastest, that is, the most environmentally friendly, is the plastic that is the plastique bag make. While the one that takes the most degradation time is the plastic bag that is the most deplorable for the environment.

3/ For composts indoors there was no evidence of compost drying. The plastic bag make with or without the bacterium Bacillus subtilis was beginning to destroy, that is, the plastic make becomes in small pieces, then for the biodegradable bag with the bacterium Bacillus subtilis, it has not changed while without the bacterium it folds back on itself. For the normal plastic bag whether inside or outside it does not change. Then the plastic made outside with or without the bacteria, it decomposed. But there are still small pieces and to finish the biodegradable plastic does not change no matter where it is.
We can conclude that for the normal plastic bag it takes more time for it to degrade. Then the biodegradable plastic bag, it also needs more time but less than the normal plastic. To finish the manufactured plastic bag, it would have taken only a few more days for it to degrade completely and therefore it is the one that takes the least time to degrade.

4/For the protocol of the earth we had difficulties, at first because of the supports because we took test tubes. They prevented us from seeing the soil and the piece of plastic properly. Then we optimized for petri dishes as a support. This allowed us to observe the earth but also the piece of plastic correctly. But unfortunately the soil was dry because of the incubation temperature. We were able to get pretty good results. That’s why we see after incubation that the land becomes very dry. In the presence or absence of Bacillus subtilis with the piece of plastic bag, biodegradable and make. Then the autoclaved soil containing the plastic bag is deposited over the mold without the bacteria and becomes dry with the bacteria. The autoclaved soil that contains the biodegradable bag becomes mud with the bacteria and becomes dry without bacteria. The autoclaved soil containing the biodegradable bag and the piece of bag made becomes dry with and without the bacteria.
To conclude, knowing that plastic bags are the most harmful to the environment, the two different types of land were not observed. We were able to conclude that autoclaved earth reacts most to plastics.

5/ The higher the concentration, the more the plastic will be degraded. In this case Bacillus subtilis (contains alpha amylase) is more effective than alpha amylase with respect to plastic. The non-degradable plastic bag at a concentration of 0.000 mg/mL so we can say that it did not degrade even after 50 minutes. We can also observe that the bag manufactured is the one in both cases where the concentration is high in a short time. It can be concluded that the bag that degrades the fastest is the plastic bag make.

6/the bacterium Bacillus subtilis is a pure strain, it degrades glucose that is to say that there is an attack of glucose only in the presence of dioxygen it is therefore an oxidative way. We observed a culture only in the presence of O2; his respiratory type is therefore strict aerobics. Finally we get an agar starch + because we observed clear halots around the culture after the addition of Lugol this indicates a hydrolysis of starch.

7/ We calculated the mass concentration of Bacillus subtilis and obtained 1.2 UFC/mL.

8/ For the Fehling protocol we obtained initially a blue tube that is to say that there is no presence of reducing sugar. It can be concluded that the solution to be tested does not contain reducing sugars. In a second step we realized with distilled water and 8 drops of glucose in a tube; we obtained a red precipitate, that is to say that there is the presence of reducing sugars.

(Experiments with a long time or we saw results. It would have taken more time, to see the total degradation of the plastic bag manufactured).


In view of all the results of the various experiments carried out, we can therefore answer the following question: "How would the use of bioplastic bags limit environmental pollution?". The best plastic bag to reduce pollution is the plastic bag made because it is the one that degrades the fastest. This is proven in the protocol of composting, with the bag which is in piece and of another color. Once we have used it, if we leave it in nature, in contact with the earth. It will degrade, about 2 months, compared to the normal plastic bag or the duration is at least 400 years. But we also know that not everyone can make their own home-made plastic bag, because some people do not have the materials and do not have the necessary means. We have a second solution, that of taking the biodegradable plastic bag, which helps to limit environmental pollution because we have proven that it destroys more slowly than the manufactured, but faster than the normal plastic. Also in contact with a high heat source, it deforms and begins to destroy. So a bioplastic bag would limit pollution because it is the second that takes the least time to degrade, it will result in limiting environmental pollution.
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