They became particularly interested in phthalates – an additive that makes plastic durable and flexible for use in a wide range of consumer products, from baby bottles to food wrap. The additive can eventually separate from the plastic and leach into the environment.
“Indian and Chinese research has shown that certain bacteria can biodegrade phthalates and we were interested to see if we could find bacteria in soil from the banks of the Fraser River estuary that would do the same thing,” says Miranda.
They also wanted to see if these bacteria occur more in polluted or pristine environments.
Mentored by Dr Lindsay Eltis at the University of British Columbia, Miranda and Jeanny, Grade 12 students at Vancouver’s Magee Secondary School, tackled the problem in three stages.
First, they collected both clean and polluted soil, grew cultures using phthalates as the only food source and isolated the different strains of bacteria. Then they identified the common bacteria in the lab by sequencing the genes and finally tested for enzyme reaction. The results were very positive and showed that the bacterial strains they identified from the “clean” site could be used to decompose phthalates.
“Bacteria are the ultimate garbage incinerators,” said Dr. Eltis, “Soils contain huge numbers of bacteria, which are essential to life on our planet.” Miranda and Jeanny’s SBCC project adds to a growing body of research into the use of common bacteria to “eat” pollutants of all kinds.
“The next logical step would be a longer-term project to see if Jeanny and Miranda could isolate bacteria which can break down more challenging and recalcitrant plastics and plastic compounds,” said Dr Eltis. “At that point there would be very definite commercial applications.”
The four month SBCC project involved 10 hours a week in the lab, but both girls consider it time well and enjoyably spent. “Dr. Eltis and the grad students we were working with, James Round and Adam Crowe, were amazing,” says Jeanny.
Both girls are taking the maximum load of science courses and plan to continue their studies after they graduate.