With all of the publicity about how plastics are piling up in landfills and the ocean there has been an assumption that the plastics are incapable of breaking down. During my undergrad as a Microbiology major at Cal Poly SLO I was interested in environmental microbiology. During this time I was given a link to an article about a Canadian teenager, Daniel Burd, who found an aerobic (grows in presence of oxygen) bacteria that can degrade plastic. Well this got me thinking, maybe the whole idea that plastics could be degraded actually made sense, I mean there are some really complex molecules in nature that can be broken down, why not the simple design of plastics. So I started planning an experiment, looking for anaerobic (grows without oxygen) bacteria that degrade plastic using a Winogradsky Column which consists of soil at the bottom of the column and liquid at the surface of the column, limiting the amount of air that can diffuse into the soil. I did this with the hope that if I could find plastic degrading bacteria I could make a microbial fuel cell which would essentially breakdown plastic and produce electricity at the same time. Yes, a little ambitious but worth a try. If you are interested in how I went through developing the procedure and results please feel free to read the following paragraphs. If you just want to get straight to business skip to the the next page!
With a vague idea of what Daniel Burd had done with his aerobic experiment I decided to design a similar experiment. In just a small sample of soil there are literally millions of bacteria, most are unable to be cultured in a lab. These bacteria and their relationships are so complicated that we may never be capable of understanding the exact ecology of a population of microbes in a spoonful of soil. With this general idea in mind it made sense to me that if put into an extreme environment, the microbes would adapt in order to survive. The nice thing with microbes is their ability to adapt quickly, turning on and off a variety of metabolic pathways to best utilize the resources available to them. That is exactly why microbes can be found almost everywhere on the planet. So my idea was to put soil microbes in an environment full of all the tasty elements they use to grow. I used Bushnell Hass Broth which is composed of Magnesium Sulfate, Calcium Chloride, Monopotassium Phosphate, Dipotassium Phosphate, Ammonium Nitrate, and Ferric Chloride. Or if you can see it better in terms of elements (Mg, S, O, Ca, Cl, K, N, H, Fe). You will notice that there is one KEY element missing from this solution, Carbon. Well lucky for us plastic is made up of Carbon (and Hydrogen) in long chains. Since Carbon is absolutely essential for microbes to grow (and all known life really) I was hoping that with all the other necessary ingredients available to them the microbes would use the Carbon found on the plastic to grow and luckily I was correct. So I will show you in just a few really simple steps how you can find plastic degrading bacteria from soil (I used landfill soil but I believe any soil would work).
Currently I am working on becoming a teacher and it is my personal belief that publishing this research for profit would really defeat the purpose.This would take away access to most people (who would have to fork over some serious cash just to look at it), especially when this could make a real, noticeable difference for a real environmental problem we face today. So I invite you to perform this experiment on your own, see what kind of results you get and collaborate our results. Please leave feedback for me in the comments, because this is my first instructable and I would like to make it the best it could possibly be. Thanks :)
With a vague idea of what Daniel Burd had done with his aerobic experiment I decided to design a similar experiment. In just a small sample of soil there are literally millions of bacteria, most are unable to be cultured in a lab. These bacteria and their relationships are so complicated that we may never be capable of understanding the exact ecology of a population of microbes in a spoonful of soil. With this general idea in mind it made sense to me that if put into an extreme environment, the microbes would adapt in order to survive. The nice thing with microbes is their ability to adapt quickly, turning on and off a variety of metabolic pathways to best utilize the resources available to them. That is exactly why microbes can be found almost everywhere on the planet. So my idea was to put soil microbes in an environment full of all the tasty elements they use to grow. I used Bushnell Hass Broth which is composed of Magnesium Sulfate, Calcium Chloride, Monopotassium Phosphate, Dipotassium Phosphate, Ammonium Nitrate, and Ferric Chloride. Or if you can see it better in terms of elements (Mg, S, O, Ca, Cl, K, N, H, Fe). You will notice that there is one KEY element missing from this solution, Carbon. Well lucky for us plastic is made up of Carbon (and Hydrogen) in long chains. Since Carbon is absolutely essential for microbes to grow (and all known life really) I was hoping that with all the other necessary ingredients available to them the microbes would use the Carbon found on the plastic to grow and luckily I was correct. So I will show you in just a few really simple steps how you can find plastic degrading bacteria from soil (I used landfill soil but I believe any soil would work).
Currently I am working on becoming a teacher and it is my personal belief that publishing this research for profit would really defeat the purpose.This would take away access to most people (who would have to fork over some serious cash just to look at it), especially when this could make a real, noticeable difference for a real environmental problem we face today. So I invite you to perform this experiment on your own, see what kind of results you get and collaborate our results. Please leave feedback for me in the comments, because this is my first instructable and I would like to make it the best it could possibly be. Thanks :)
Remove these ads by
Signing UpStep 1: Materials
First you need your materials:
- At least 1 empty 2 liter Soda Bottle (cut the top off, see pictures below. I used 4)
- Bushnell Hass Broth (http://www.sigmaaldrich.com/catalog/product/FLUKA/B5051?lang=en®ion=US)
- Soil (try to dig down a few feet for a better chance of finding anaerobic bacteria)
- An accurate scale (preferably accurate to the thousand ex: 2.008g)
- Cut up strips of plastic bags
- Petri dishes and agar (I used TSA, Oatmeal agar, and Czapek agar just to have a nice variety)
- Autoclave
- Sealable test tubes
- Sterile gloves
- Bunsen Burner
- Tweezers
- Inoculating Loop
- At least 1 empty 2 liter Soda Bottle (cut the top off, see pictures below. I used 4)
- Bushnell Hass Broth (http://www.sigmaaldrich.com/catalog/product/FLUKA/B5051?lang=en®ion=US)
- Soil (try to dig down a few feet for a better chance of finding anaerobic bacteria)
- An accurate scale (preferably accurate to the thousand ex: 2.008g)
- Cut up strips of plastic bags
- Petri dishes and agar (I used TSA, Oatmeal agar, and Czapek agar just to have a nice variety)
- Autoclave
- Sealable test tubes
- Sterile gloves
- Bunsen Burner
- Tweezers
- Inoculating Loop
Visit Our Store »
Go Pro Today »
My 2 cents are that probably you need to test on different materials. It's a shame you lost your specimens. This is something quite important for the future.
I love reading your stuff, makes me excited, though I know I have no time to try it out myself. Would love to read more!
Maybe one day...
How far is your new experiment?
Do you think it would be possible to internationally ship bacteria? Maybe I could do the first step of your experiment and ship you my bacteria, so you have a higher variety of bacteria from diferent places... Or just some soil...
Im not sure on the rules of shipping soil and bacteria but I have a feeling you might get in trouble for doing it. Maybe its worth looking into but in the meantime your more then welcome to try it out for yourself and we can see where your at in a few months. Are you located in the US?
So maybe I'll try it in summer (if you remember, remember me :P).
Im doing an experiment with the same general idea of yours the diffrence is im going to use a concentrated colony of bacteria in this case im going to use 2 indepent and 1 control the control is the standard soil while the independent is going to be with the sphingomonas 2MPII and Pesudomonas alcaligenes.
DO you think this experiment would work? do you have any comment or anything ? i will do this for abou 3-4 months. And im in high school just so you know one more thing is there anymore bacteria that have the slightest possibility to degredade plastic espesccialy oxium plastic.... After the experiment i'll make sure to give the full result thank for your help in advance :D
-Ryan
I have a question. Where could you find a growth medium consisting of 0.1% (NH4)2SO4, 0.1% NaNO3, 0.1% K2HPO4, 0.1% KCl, 0.02% MgSO4, and 0.01 % yeast extract? I want to do the Plastic not Fantastic experiment by Daniel Burd that you based this experiment off of. Any help would be the best!
Alexis
If you made up these amounts I guess you could always just make it yourself?
Let me know!
I can barely wait to try this with a class! I'm a undergraduate on physics so I'm not an expert on microbial life nor plastic compounds, but I'll do as you said and then try to analyze the results.
Given that plastics largely consist of hydrocarbons, they themselves could be used as fuel. But from my understanding, we have difficulties with making fuel (ethanol OR petroleum) from cellulose, so maybe it's too ambitious to do this without some way to remove potentially toxic additives...
Did you end up finding which bacterial species were happily munching up the plastic?
You are absolutely correct that the hydrocarbons in plastic can be made into fuel. There was actually a Japanese inventor who was able to make a machine that essentially melted the plastic bags into a kind of crude oil, there is actually a video if you are interested (http://alttransport.com/2011/02/a-machine-that-converts-plastic-bags-into-fuel/)
Based on what I have read about I would say that most crops that are used to make ethanol (corn for example) really don't make much economical sense and don't really help with food prices. I think there is an increased amount of research for easier growing alternatives, like algae and switchgrass. In terms of toxic additives, I'm sure there are multiple additives, but I would think they would be considered generally safe since plastic bags are of such common use. In terms of this experiment I think the first step is to make sure that there is the most efficient degradation, and then worry about getting rid of any potential additives.
I never identified the several species I isolated, I graduated right after I obtained my results and the samples were not stored properly so they were lost. So I have to do the experiment again :)