Black soldier flies can be used to address two of Australia’s largest environmental problems: food waste and plastics pollution. Australia produces 7.6 million tonnes of food waste annually, and 84 per cent of the nation’s plastic waste ends up in landfill every year. Research now underway at Southern Cross University is delving into the many ways black soldier fly farms can be useful in Australia – including the production of high-protein animal feed and organic fertiliser, and even weed control.
Black soldier fly larvae can consume organic waste at an astonishing rate, limiting food waste greenhouse gas emissions and reducing landfill. At the same time, the chitin – or exoskeleton – of the flies’ pupae can be treated to become the basis for a natural biodegradable polymer, or bioplastic.
Originally from South and Central America, black soldier flies have now spread around most of the world, says university program leader Lachlan Yee, and they are not considered a threat to the Australian environment.
Southern Cross University senior lecturer Lachlan Yee. Picture: Natalie Grono
“We’re keen to look at black soldier flies and some of these questions that are coming up in the research field,” he adds. “For example, Stephen Meyers, an American professor, has found that the tea (leachate) derived from black soldier fly frass (droppings) can actually slow down the growth of weeds in the US.” Yee wants to determine whether this leachate has the same effect on Australian weeds.
As well as food waste, black soldier flies can consume faeces, including cattle and sheep droppings and human excrement, suggesting applications for agricultural waste management.
Yee explains that black soldier fly technology has been in use in compostable toilets for some time now. The black soldier fly’s adult lifespan is only three to seven days, on average, and adult flies have no moving mouth parts so they cannot consume anything when they’re adult and mobile, Yee says.
Most of the flies’ total lifespan in the larval stage is as detritivores, or scavengers, he adds, when they consume rotting, semi-liquefied biowaste and potentially many other types of waste now destined for landfill.
One female adult black soldier fly can produce between 200 and 400 eggs and the resulting larvae can consume twice their body size in waste in a day.
The university also has research underway on scalable business models of black soldier fly farming and how they best fit into both regenerative and circular economies. From large-scale operations in Europe and Asia to Australian start-ups, black soldier fly farm enterprises have a growing presence around the world, and current research suggests the massive potential of future applications.
One increasingly important research arm, Yee says, is the development of “chitosan” from black soldier fly chitin or exoskeletons. Chitosan could potentially replace some of the single-use synthetic plastics that now clog landfill, waterways, and the ocean, and also potentially replace the wax-like substances now sprayed onto fruit and vegetables.
“I want to use insects to generate the next generation of plastics, because the chitosan we make from the black soldier flies is completely biodegradable,” Yee says.
Chitosan is not yet as robust as today’s single-use plastics, he adds, but “clever chemistry can start to bridge that gap”.