Insects and microalgae are increasingly catching the attention of EU producers and consumers. They pose as two of the most promising alternative sources of protein to more conventional sources such as meat or soy. Not only are they rich sources of nutrients – such as proteins and healthy fats – but they can also grow fast while having the potential to have a small carbon footprint.

So, how can insects and microalgae join paths on the road to a circular economy and help support resource-efficient food systems in the future?

In this article, we’ll take a closer look at how ProFuture’s partner, NORCE is researching the use of insect waste as a source of nutrients to grow microalgae. The main goal is to assess the potential of replacing chemical nutrients with organic insect waste and see how it affects the growth and nutritional quality of the final biomass.

Towards sustainable food production processes – the NORCE example

The European Green Deal plan aims to achieve a modern, resource-efficient and competitive economy. In other words: an economy that gives back to the planet more than it takes and keeps the consumption of natural resources within planetary boundaries, while still thriving. (1)

Since half of total greenhouse gas emissions and more than 90% of biodiversity loss and water stress come from resource extraction and processing, food systems play a key role in the transition towards a sustainable economic model.

Besides studying new sources of nutrients – such as microalgae – Europe is focused on finding innovative ways to reduce waste, improve sustainability and increase the efficiency of food production systems. Fuelled by this mission, NORCE has been exploring the potential of microalgae production as a “self-sufficient” process.

At NORCE, the production of microalgae already takes advantage of many renewable resources available around. The water comes from the sea bathing the Norwegian coast and the electricity comes from hydropower. Even carbon dioxide is supplied by a carbon capture pilot plant (Technology Centre Mongstad), which traps carbon dioxide produced by industrial activities before it is released into the atmosphere.

Growing microalgae in a circular economy model. Where do insects come in play?

Microalgae can grow under different conditions. Some grow using sunlight, water and carbon dioxide (autotrophic species). Others can grow in the dark, using other sources of organic carbon such as sugars, instead of carbon dioxide (heterotrophic species) and others can grow using both methods, depending on the conditions available (mixotrophic). Moreover, they all use chemical fertilizers – also used in conventional agriculture - as a source of nutrients, such as phosphorus and nitrogen.

But one of the key actions under the Farm-to-Fork strategy is to reduce food, water and nutrients waste within the food value chain, by helping to efficiently use, reuse and recover such biological resources. In fact, by 2023 all EU countries must halve per capita food waste - at the retail and consumer level - and reduce food losses along the food production and supply chains.(2)

So what if we could recycle nutrients to feed microalgae and still get a nutritious and safe to eat biomass?

To test this hypothesis, NORCE conducted preliminary experiments to study the growth of microalgae species (Nannochloropsis and Tetraselmis) using different side streams, such as:

• organic municipality waste (from household food waste)
• insect frass (from the excrements and the exoskeleton)
• fish sludge (from the excrements and uneaten feed)
• wastewater from the fish processing plant
• municipality wastewater from a water treatment plant
• wastewater from a beer brewery

These preliminary studies showed that microalgae fed with insect waste could grow faster, due to the high bioavailability of their nutrients. In other words, insect waste provided a variety of important nutrients in a form that algae could easily take them up (absorb) and use them to grow and multiply.

To understand its full potential, NORCE is now setting up more complex studies. The goal is to assess what are the optimal conditions to grow microalgae with insect fertilizer. This implies:

• analysing the nutritional quality of the insect waste (the type and amount of nutrients, such as nitrogen and phosphorous, that they contain) and see if how efficient the algae can convert the insect frass into algae biomass;
• compare the nutritional quality of the microalgae obtained from insect fertilizer and others cultivated with a regular fertilizer.

Fig.2 – Growth medium based on insect frass after two types of pre-treatment (left) and insect frass (right).

Scalability and future challenges

Insects can be used to produce many commodities, including food and animal feed. They can use organic wastes to feed on (such as used grains from beer production or organic food waste). In this process, there’s also waste, mainly consisting of the excrements and exoskeletons of the insects. That waste can then be used for other purposes, such as to make fertilizers for agriculture, which in turn help to grow food again. This is the very core of a circular economy.

With insect production foreseen to grow worldwide, there’s also the need to tackle insect waste – including a possible surplus of insect fertilizer – and microalgae could present as a solution. However, understanding the scalability and the economic benefits of this process still needs further research, as both insect and microalgae production are only now gaining traction in Europe.

Nevertheless, a few challenges arise from this circular process, the three main ones being related to: conversion efficiency, nutritional value and regulatory affairs.

1) Conversion efficiency - transforming insect fertilizer into microalgae feed.

Insect fertilizer is a dry powder which needs to be dissolved in water (a process that also needs to be optimised) to be taken up by microalgae. As so, one thing that needs to be clearly understood is how much insect fertilizer can be converted into microalgae feed.

The second question is how much insect fertilizer is needed to grow high amounts of microalgae? Would it be needed in lesser amounts than other conventional feeds to produce the same (or even higher) mass of microalgae?

These first two questions are currently being studied at NORCE.

2) Assessing the nutritional quality of the final biomass

Another important question is to understand how or if the nutritional quality of the microalgae is affected by the use of insect fertilizer.

In previous studies, NORCE has seen positive results (i.e. a higher content) on the omega-3 fatty acids content of three marine species of microalgae grown with insect waste. For ProFuture, NORCE will conduct similar trials using a freshwater microalgal species (Chlorella vulgaris) and assess how the protein content and quality of the fully-grown microalgae is affected.

3) Labelling and regulatory affairs

Food and fertilization laws play a big role in food production and there are still many grey areas when it comes to novel food. For example, microalgae include a wide range of species with varying characteristics and there’s no consensual definition for “microalgae” in the EU.(3)

This affects what regulations/directives guide their production rules. For example, when the production process of microalgae is similar to that of seaweed, the rules for production should fall under the scope of the Regulation (EC) No 889/2008. However, no detailed production rules have been specified for microalgae used for food and feed, which can pose some challenges when trying to use side streams to “fertilize” or “feed” them.

This could also affect if microalgae grown with insect fertilizer could receive the “vegan” seal.4 While some some vegans would only consider the use of animal products after harvesting when choosing food products, others might not accept that organic waste from insects is used to nurture microalgae.

Stay tuned to know more about ProFuture’s research on using insect waste to grow microalgae and if it can be a viable option for the future.

References

1. European Comission (EC). (2020). Circular Economy Action Plan. For a cleaner and more competitive Europe. https://ec.europa.eu/environment/circular-economy/pdf/new_circular_economy_action_plan.pdf

2. European Comission (EC). (2020). The Farm to Fork Strategy. https://ec.europa.eu/food/farm2fork . Accessed 12 Mar 2021

3. European Algae Biomass Association (EABA). (2019). What are algae? https://www.what-are-algae.com/ . Accessed 12 Mar 2021

4. European Vegetarian Union (V-Label). By what criteria are products carrying the V-Label marked as vegan or vegetarian? https://www.v-label.eu/en/faq . Accessed 12 Mar 2021