SCIENCE BLACK SOLDIER FLIES LOVE TO CHEW OVER PROBLEM OF HOW TO RECYCLE FOOD WASTE
UAE ideally suited to larvae that consume up to four times their weight of food waste every 24 hours to produce a nutritious animal feed, writes Daniel Bardsley
Excessive food waste has become a global epidemic but the UAE may have found the answer buzzing right under our noses. A recent study by the UN Food and Agriculture Organisation found that 1.3 billion tonnes of food – about one third of that produced globally – is lost or wasted every year.
During a recent visit to Singapore, Mariam Al Mehairi, Minister of State for Future Food Security, was shown an emerging technique that could change how food waste is processed.
The larvae of the black soldier fly plays a central role in the method.
Like all maggots, black soldier fly larvae are creatures that few of us find attractive. But they are especially useful in their ability to process food waste, and as a source of nutrition.
At the National University of Singapore, Ms Al Mehairi learnt about how this fly can turn food waste into two useful products. They are plant fertiliser produced by larvae from the waste, and animal feed.
The animal feed that the black soldier fly produces is rich in proteins, fats and chitin – the material from which their shells are made.
Few organisms are more accomplished at eating than black soldier fly larvae. In one day they can consume four times their body weight. That means that 100 kilograms of larvae can process hundreds of kilogram s of food waste every 24 hours. And there is no waste product generated.
There are several factors that make the soldier fly particularly suited to recycle food. It is not picky about what it eats, so it can deal with a wide variety of food waste. It does not spread disease and is found in most regions of the world.
But although the species is ideal for dealing with food waste, scientists are determined to make it even better.
Researchers at the university, including Prof Rudolf Meier, are trying to create black soldier flies that grow faster, lay more eggs and can deal with even larger quantities of surplus food.
“The flies that are currently used for recycling have not been ‘domesticated’,” said Prof Meier, who works in the university’s department of biological sciences.
“If we compare wild species to their domesticated cousins, we routinely find that the domesticated animals and plants perform much better. We expect the same to happen to black soldier flies once they are domesticated. They will be much more efficient at recycling food waste.”
The UAE, which aims to recycle 75 per cent of food waste by 2021, is perfect for the system because the flies grow faster and reproduce all year in warmer climates.
“This means that the cost of using these flies will be lower in tropical and subtropical countries,” Prof Meier said.
The flies are already used for recycling organic waste in many countries and, once they are domesticated, he is confident that they will be used even more widely.
One factor that could promote their use is the need for alternative animal feeds. There are concerns over future supply of another feed, fishmeal, because of fishing quotas, and increased in demand for fishmeal to feed farmed fish.
Fishmeal is regarded as less than sustainable, because it can be made from wild fish in one area, then sent to fish farms halfway across the world. There are also sustainability concerns linked to another animal feed, soya.
So there is little doubt that the material the flies produce when they break down food waste could prove useful. But are there better methods of dealing with food waste?
Aside from putting it in landfill sites, incinerating and composting, the most established processing method is anaerobic digestion, which involves micro-organisms digesting the waste in the absence of oxygen.
The end products are fertiliser and gases, primarily methane, which can be turned into energy.
Prof Stephen Smith at Imperial College London said anaerobic digestion was well-established and cost-effective.
“It’s a very concentrated fertiliser product,” Prof Smith said. “It’s more nutritious but it needs to be carefully managed in terms of the crop requirements. That’s not a disadvantage but it needs a higher level of input.”
Anaerobic digestion also requires less space and labour than black soldier flies, although researchers working with the insects are seeking to address such concerns.
Prof Meier believes there are several advantages in using black soldier flies rather than anaerobic digestion. Both of the products generated by the black soldier fly are revenue sources that “help with food security”.
“In contrast, the main product obtained via anaerobic digestion is moderate amounts of biogas, which is a lower-value product compared to animal feed,” he said. “In addition, anaerobic digestion requires water that has to be treated after digestion.”
Critics say anaerobic digestion needs substantial investment. The black soldier fly could be a lower-tech, lower-cost solution.
With improvements in the flies likely, Prof Meier is hoping for a substantial increase in take-up.
“Once domesticated, they will certainly be used even more widely,” he said.
And after Ms Al Mehairi’s visit, perhaps the UAE will be one of the beneficiaries.
The cost of using these flies will be lower in tropical and subtropical countries, such as UAE PROF RUDOLF MEIER Researcher at the National University of Singapore