Meet the black soldier fly: The new weapon in the war against food waste

The humble insect is being enlisted to help tackle the global epidemic of excessive food waste

Black soldier fly larvae are being in used in many countries to tackle food waste. Courtesy National University of Singapore.  

Excessive food waste has fast become a global epidemic - but the UAE may have found the answer buzzing right under our noses.

A recent study by the United Nations' Food and Agriculture Organisation found that 1.3 billion tonnes of food - roughly one third produced globally - is lost or wasted every year.

During a recent visit to Singapore, Mariam Almheiri, the UAE Minister of State for Future Food Security, was shown an emerging technique that could transform how food waste is processed.

A humble creature called the black soldier fly – or, to be more precise, its larvae – plays a central role in this alternative method.

Like all maggots, black soldier fly larvae are creatures that few of us would find attractive. But they are especially useful in their ability to process food waste and in themselves as a source of nutrition.

At the National University of Singapore (NUS), Ms Almheiri learned about how this fly, known scientifically as Hermetia illucens, can turn food waste into two useful products: plant fertiliser (produced by the larvae from the food waste) and animal feed (what the larvae become). The animal feed that the black soldier fly produces is rich in proteins, fats and chitin, the material that their shells are made from.

Few organisms are more accomplished at eating than black soldier fly larvae: in a single day they can consume four times their body weight. That means that 100kg of larvae can process hundreds of kilograms of food waste every 24 hours.

What makes the method all the more impressive is the amount of waste product that it generates – precisely zero.

There are a number of factors that make black soldier flies particularly suited to being a food recycler. It is not especially picky about what food waste it chomps its way through, so it can deal with a wide variety of material. Also, it does not spread disease and it is a very widespread species, being found in most regions of the world.

But, although the species is already an ideal choice for dealing with food waste, scientists are determined to make it even better.

Researchers at NUS, including Professor 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.

This super soldier will be well equipped to wage war on food waste in the UAE.

“The flies that are currently used for recycling have not been 'domesticated',” said Prof Meier, who is part of NUS'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 percent of food waste by 2021, is just the kind of nation where the system would work, because the black soldier fly grows faster and reproduces year-round in warmer climates.

“This means that the cost of using these flies will be lower in tropical and subtropical countries,” said Prof Meier.

Black soldier flies are already used for recycling organic waste “in many countries” and, once they are domesticated, Prof Meier is confident that they will be employed yet more widely.

One factor that could promote their use is the need for alternative animal feeds. There are concerns over potential future limitations in the supply of another feed, fishmeal, because of fishing quotas, and increased in demand for fishmeal to feed farmed fish.

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Also, fishmeal is sometimes seen as less than sustainable, since it can be made from wild-caught fish in one area before being sent to fish farms halfway across the world. There are also sustainability concerns linked to another alternative animal feed, soya.

So there is little doubt that the materials that black soldier flies produce when they break down food waste could prove useful. But are there better methods of dealing with food waste?

Aside from putting 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.

Professor Stephen Smith, a professor of bioresource systems at Imperial College London, described anaerobic digestion as “well-established” and “cost-effective”.

“It's a very concentrated fertiliser product. 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,” he said.

Anaerobic digestion also requires less space and lower labour inputs than using black soldier flies, although multiple research projects involving the flies are looking to address such concerns.

NUS's Prof Meier sees 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. In addition, anaerobic digestion requires water that has to be treated after digestion,” he said.

Anaerobic digestion has also been criticised for requiring substantial investments to get going and for relying on subsidies. The black soldier fly could be a lower-tech, lower-cost solution.

At the moment, Prof Smith sees scale of use of black soldier flies as “embryonic” and at the moment does not see it taking a substantial market share.

“I think it's probably quite niche,” he said.

Yet with improvements in the flies on the horizon, 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 Almheiri's visit, perhaps the UAE will be one of the beneficiaries.