This looks the makings of a great new company:
Getting ordinary plastic bags to rot away like banana peels would be an environmental dream come true.
After all, we produce 500 billion a year worldwide and they take
up to 1,000 years to decompose. They take up space in landfills, litter
our streets and parks, pollute the oceans and kill the animals that eat
them.
Now a Waterloo teenager has found a way to make plastic bags degrade faster — in three months, he figures.
Daniel Burd’s project won the top prize at the Canada-Wide
Science Fair in Ottawa. He came back with a long list of awards,
including a $10,000 prize, a $20,000 scholarship, and recognition that
he has found a practical way to help the environment.
Daniel, a 16-year-old Grade 11 student at Waterloo Collegiate Institute, got the idea for his project from everyday life.
“Almost every week I have to do chores and when I open the
closet door, I have this avalanche of plastic bags falling on top of
me,” he said. “One day, I got tired of it and I wanted to know what
other people are doing with these plastic bags.”
The answer: not much. So he decided to do something himself.
He knew plastic does eventually degrade, and figured
microorganisms must be behind it. His goal was to isolate the
microorganisms that can break down plastic — not an easy task because
they don’t exist in high numbers in nature.
First, he ground plastic bags into a powder. Next, he used
ordinary household chemicals, yeast and tap water to create a solution
that would encourage microbe growth. To that, he added the plastic
powder and dirt. Then the solution sat in a shaker at 30 degrees.
After three months of upping the concentration of plastic-eating
microbes, Burd filtered out the remaining plastic powder and put his
bacterial culture into three flasks with strips of plastic cut from
grocery bags. As a control, he also added plastic to flasks containing
boiled and therefore dead bacterial culture.
Six weeks later, he weighed the strips of plastic. The control
strips were the same. But the ones that had been in the live bacterial
culture weighed an average of 17 per cent less.
That wasn’t good enough for Burd. To identify the bacteria in
his culture, he let them grow on agar plates and found he had four
types of microbes. He tested those on more plastic strips and found
only the second was capable of significant plastic degradation.
Next, Burd tried mixing his most effective strain with the
others. He found strains one and two together produced a 32 per cent
weight loss in his plastic strips. His theory is strain one helps
strain two reproduce.
Tests to identify the strains found strain two was Sphingomonas bacteria and the helper was Pseudomonas.
A researcher in Ireland has found Pseudomonas is capable of
degrading polystyrene, but as far as Burd and his teacher Mark
Menhennet know — and they’ve looked — Burd’s research on polyethelene
plastic bags is a first.
Next, Burd tested his strains’ effectiveness at different
temperatures, concentrations and with the addition of sodium acetate as
a ready source of carbon to help bacteria grow.
At 37 degrees and optimal bacterial concentration, with a bit of
sodium acetate thrown in, Burd achieved 43 per cent degradation within
six weeks.
The plastic he fished out then was visibly clearer and more
brittle, and Burd guesses after six more weeks, it would be gone. He
hasn’t tried that yet.
To see if his process would work on a larger scale, he tried it
with five or six whole bags in a bucket with the bacterial culture.
That worked too.
Industrial application should be easy, said Burd. “All you need
is a fermenter . . . your growth medium, your microbes and your plastic
bags.”
The inputs are cheap, maintaining the required temperature takes
little energy because microbes produce heat as they work, and the only
outputs are water and tiny levels of carbon dioxide — each microbe
produces only 0.01 per cent of its own infinitesimal weight in carbon
dioxide, said Burd.
“This is a huge, huge step forward . . . We’re using nature to solve a man-made problem.”
Burd would like to take his project further and see it be used.
He plans to study science at university, but in the meantime he’s busy
with things such as student council, sports and music.
“Dan is definitely a talented student all around and is poised
to be a leading scientist in our community,” said Menhennet, who led
the school’s science fair team but says he only helped Burd with
paperwork.
Other local students also did well at the national science fair.
Devin Howard of St. John’s Kilmarnock School won a gold medal in life science and several scholarships.
Mackenzie Carter of St. John’s Kilmarnock won bronze medals in the automotive and engineering categories.
Engineers Without Borders awarded Jeff Graansma of Forest
Heights Collegiate a free trip to their national conference in January.
Zach Elgood of Courtland Avenue Public School got honourable mention in earth and environmental science.