Newfoundlander Jennifer Murphy turned a childhood love of marine creatures into award-winning PhD research that is changing the province’s aquaculture industry.
When Jennifer Murphy was growing up in Portugal Cove, NL, her father would take her cod jigging, a uniquely Newfoundland way of fishing that involves throwing a piece of baited line with hooks into the water, then letting it sink. As the line is retrieved, it is tugged, or jigged, attracting and (hopefully) snagging a cod for the evening meal.
As she sat in her dad’s boat, Murphy would look towards the shoreline, imagining all the creatures she’d find exploring the intertidal zone: crabs crouched under rocks, sea stars, chitons, anemones, as well as innumerable species of mussels. It perhaps isn’t surprising that Murphy would end up devoting her PhD chemistry studies at Memorial University of Newfoundland (MUN) in St. John’s to the study of blue shell mussels, devising new applications for materials derived from this tasty bivalve mollusc. Her work is so diverse, she describes it as a combination of physical, inorganic, materials and analytical chemistry. “I’m a chameleon chemist,” she quips.
Following an award-winning honours BSc degree at MUN spent exploring crystals and metal complexes, Murphy leaped into a PhD in 2014. Her focus this time around — adding value to waste mussel shells — was inspired by the growth in mussel farming in response to increasing global demand for protein. Because mussels are 70 percent shell, this creates huge amounts of odoriferous waste in the landfill. (It is illegal to dump shells in the ocean.) Surely, thought Murphy, there was a chemical solution to the problem. She set out to find one, visiting provincial mussel farms and processing plants. Not only did Murphy succeed in addressing the waste problem, she did it using green principles.
Mussel shells are made primarily of calcium carbonate (CaCO3). Since CaCO3 is a base, it has a myriad of potential uses. Not only can it be used to neutralize acidic soil, it can be broken down into lime as a lawn additive. It is also used in cosmetics, adsorbants, in building materials, for cleaning wastewater drainage lines and can be used to make hydroxyapatite, a substance in dental implants.
But before the shells can be put to use, the flesh must be removed. Shucking mussels is a messy process and leaves behind a fair amount of biological protein. Currently, processors use a harsh acid treatment to destroy the protein — Murphy’s solution was inspired by nature. Her improved process uses biocatalysts and natural enzymes (provided by DuPont through an NSERC Engage Grant) that clean shells and create new materials from the waste. “The idea was to hydrolyze the mussel meat directly from the shell without grinding,” says Murphy.
The new process spawns two streams of materials. One stream is protein hydrolysate from the flesh of mussels either too small to sell or cracked. Murphy uses it to make fish food. The other stream is the shells themselves. In addition to the applications listed above, Murphy has also created her own business (she is still deciding on a name), devising an additive for nail varnish from mussel shells. The additive gives nail polish a gleaming, pearly lustre, says Murphy, who is considering patenting her trendy discovery.
Murphy’s research netted her the Oral Presentation Award this past June at the 99th Canadian Chemistry Conference and Exhibition in Halifax. With the help of an undergraduate student, Murphy is up-scaling CaCO3 extraction for use in additional applications. One idea includes replacing the calcium chloride — “which is not very friendly to nature” — currently used in Newfoundland as road salt with calcium acetate, which acts as a de-icer. “I want to do research forever,” Murphy says. “The lab is probably my favourite place in