Scaling gas fermentation technology to market-size animal feed protein production

Our CTO Rob Mansfield gives his perspective on why he believes the scalability of gas fermentation makes it a leading candidate in the race to revolutionise the animal feed industry.

Demand for animal protein and nutrition continues to proliferate. The requirement for high-protein ingredients such as fishmeal and soybean protein concentrate in global feed salmon, shrimp and poultry markets is predicted to reach nearly 60 million tonnes in 2035.

Simultaneously, global challenges such as a rising global population, natural resource depletion and the climate crisis mean the need for more sustainable and efficient alternatives of feed production is higher than ever. Robert Mansfield, Co-Founder and Chief Technology Officer of Deep Branch, explores the development of new sustainable technologies that will replace traditional fossil fuel-intensive methods of producing animal feed. He also examines current industry adoption, interest and the challenges and opportunities these new technologies offer.

The current state of play

Human fish and meat consumption are increasing globally, despite the increased awareness of alternative diets such as veganism. Additionally, all regions of the world are expected to see high growth in food protein consumption, with Asia and South America leading the way. Therefore, the global demand for animal feed continues to grow.

Animal feed production is an increasingly consolidated industry with a decreasing number of prominent players. Without effective incentivisation for change, the monopolistic tendencies associated with heavily consolidated commodity markets represent a potential barrier to the necessary adjustments the industry requires, including the introduction of alternative production methods and more sustainable ingredients.

Breaking away from conventions

The carbon footprint associated with conventional animal feed production methods and the products available today are renowned for being high. For example, aquafeed typically contributes over 80% of the carbon intensity of farmed salmon before it is distributed to supermarkets for the public to purchase.

However, other direct and indirect ecological impacts caused by the production of the major incumbent feed ingredients are often poorly factored into sustainability accounting methods based on carbon dioxide emissions. The best documented ecological effects associated with animal feed production relate to the production of the primary protein ingredient by volume, soybeans, and include the sometimes irreversible biodiversity losses and soil erosion associated with mass deforestation of global rainforests. Unfortunately, such practices are an all too familiar preparation step for environmentally intensive agriculture methods associated with many large-scale soy production systems, which are themselves often implicated in the pollution of local water courses. Furthermore, the destruction of deep-sea environments through aggressive trawling methods means that the production of fishmeal, the second most prevalent protein inclusion in animal feeds, is little better ecologically.

The good news is that animal feed can be produced sustainably in terms of carbon footprint and ecological impact. Crucially, this enables sustainable food production without requiring a seismic population-level change to people’s current diets to achieve this. The choice of veganism, vegetarianism, and reduced meat consumption empowers individuals to materially reduce their personal environmental impacts. However, the scale and pace of societal change required to mitigate the effects of the (un)sustainability of today’s human diet on a population level need us to consider new solutions to improve the sustainability of all existing diets.

Sustainable alternatives are on the horizon

Insect meal is the sustainable alternative that has received the most public attention. The industry perception of this ingredient is that it’s palatable and has a place in larger animal feed markets due to its nutritional profile. As a result, it is approaching the point of being commercially available at scale. Secondary traditional waste streams, such as meals derived from farming wastes like blood and feathers, are already well established in various animal feed markets as more sustainable supplements to the primary bulk feed ingredients, soy and fishmeal. However, these are limited in scalability due to reliance on their respective primary industries.

Single-cell protein is an umbrella term covering many potentially excellent ingredient alternatives. Some single-cell proteins, such as those derived from the fermentation of sugar beet waste, are already commercially available. In contrast, others, like those derived from methane and algae, are newer to the market.

The positives and the negatives

There are both positives and negatives for these sustainable animal feed protein alternatives. For instance, nutritional tailoring of existing products is easy with single-cell protein, certainly relative to plant-based systems, for example. This is a combined result of an immense naturally-occurring diversity of single-celled organisms, tight control of production conditions during fermentation, and rapid development cycles for new and optimised products. Insects, meanwhile, are often heralded for containing easily digestible protein and a good balance of essential amino acids for the diets of many farmed animals, which is likely at least a partial result of natural dietary evolution across animal species. Additionally, protein sources derived from existing agricultural and horticultural waste streams, such as blood and feather-meals, are already well set up within existing supply chains and the infrastructure needed to produce animal feed.

One of the main challenges facing these sustainable alternatives and perhaps all new types of animal feed is scalability. Scalability is an important criterion for driving new product adoption in the feed markets, particularly for bulk feed ingredients. It is improvements in this space where the most significant sustainability benefits can be realised. The traditional methods for producing feed are long-established, so there has to be a substantial push from major industry players to move away from the likes of fishmeal and soybean protein concentrate to focus on new sustainable alternatives. Ensuring the scale and availability of any alternative ingredient is crucial in incentivising uptake by compound feed producers. This is particularly relevant where driving engagement and transactions on new ingredients based on sustainability credentials alone has been challenging in the comfortable and well-established feed markets. The scalability of insects is under particular scrutiny before it can take a commercially leading position. Specifically, insect systems must demonstrate successful scaling of the process using sustainable feedstocks based on waste streams from other industries. Such waste streams have historically created issues due to inherent and hard-to-deal-with variability at scale. Other sustainable technologies have fallen at this hurdle after showing comparable initial promise at pilot and demonstration scales. Validating the required robustness of the insect production systems against these inherent feedstock risks will be critical.

The benefits of gas fermentation

I was very excited when I first heard of gas fermentation, as it represented a technology platform with enormous potential. Gas fermentation connects two completely different industries upstream and downstream of the process. From the upstream perspective, this is a novel gas utilisation technology. From the downstream perspective, it unlocks previously unusable feedstocks for producing various fermentation products. Essentially, gas-fermentation technology offers a means of creating high-value biological or biologically-derived products from inputs traditionally not associated with the end markets for these, and the opportunities are enormous.

At Deep Branch, we focus on a particular branch of gas fermentation which uses three primary gas inputs: hydrogen, carbon dioxide and oxygen. Using these gases as feedstocks opens up possibilities for creating more sustainable fermentation products, as they can each be produced using sustainable technologies or secured as secondary waste products of other processes. Each gas is already produced for or by other industries at orders of magnitude greater than that which would reasonably be required to service the production of product for the animal feed sector.

To engage effectively with animal feed markets and make a material impact in a challenge as enormous as the sustainability of global human diets, scalability is vital. Fermentation systems are typically scalable in three dimensions, meaning that large-capacity production units can be built on a relatively small footprint. This is the opposite of traditional farming, which scales in two dimensions. As a result, expanding production capacity in traditional farming inevitably requires additional arable land, often associated with deforestation practices.

However, not all fermentation systems are equal. Significant differences arise from the unique feedstock-feeding and product-harvesting regimes of each process.

Submerged liquid fermentations are the most commonly used commercial systems, providing all the required nutrients for fermentation dissolved within a liquid broth. Gas fermentation is a subset of this type of fermentation, unique because the major carbon and energy source nutrients are added in gaseous form rather than pre-dissolved in liquid. The production rates achievable in submerged liquid systems are high due to the excellent availability of nutrient feedstocks throughout the liquid phase, where production ultimately occurs. This is crucial in achieving high production capacities from facilities with relatively small footprints.

Scaling submerged liquid fermentation is largely a challenge of achieving as close to uniformity of internal conditions, such as nutrient availability and temperature, as possible in larger and larger vessels. Contrast this with photo-fermentations which use photosynthetic algae, another potentially good system for producing alternative proteins and other feed ingredients. The scaling of this technology is more challenging because light, the energy source for these fermentations, must be available throughout the production process. Because the substance inside these bioreactors is a relatively dense milky consistency, light does not penetrate well, so scaling cannot rely on bigger vessels. Maximising nutrient gas-to-liquid transfer in gas fermentation is a similar issue and arguably one of the most significant challenges to successfully scaling up the technology. However, getting bubbles to move through a milky broth is more straightforward than doing so with light. Several tweakable factors can be controlled and optimised to encourage the nutrient-containing gas bubbles to transfer faster into the liquid.

Overcoming barriers to broader adoption

The animal feed sector is vast and continues to grow at pace alongside the rising demand for animal products. However, there are increasing limitations on further scaling of the incumbent protein ingredients. Most notably, real-world limits on global fish stocks cap the amount of fishmeal that can be reasonably produced annually. Meanwhile, international pressure to limit further deforestation worldwide hinders any significant expansion of soy production. As such, there is a genuine opportunity for alternative protein sources to step up and fill the gap in the availability of suitable protein.

A single silver bullet solution will unlikely replace the traditional method of producing animal feed. However, gas fermentation looks well-equipped to become one of the major players in this new space of alternative approaches. Fermentation concepts have been successfully developed for centuries, from beers to wines and everything in between, so there is reliable evidence that these technologies scale well.

For gas fermentation to make a significant impact, all stakeholders in the value chain will need to buy into the vision. This includes feed producers, the de-facto gatekeepers for market entry for any new ingredient. BioMar and AB Agri are two examples of feed producers backing gas fermentation by trialling proteins derived from the technology in its products.

The success of the development work over the coming years will also rely heavily on the support of well-aligned investors to provide the financial backing required for the realisation of the technology scale-up and commercialisation strategy. DSM, Novo Holdings and Barclays’ Sustainable Impact Capital initiative are several investors in the sustainable feed and food ingredients space to have invested in gas fermentation technologies. Despite the global economic uncertainty the world faces, this increasing financial interest in gas fermentation’s potential signals an increasingly shared understanding and alignment of the importance and value of technologies such as this over the coming decades.

How will the industry look in the future?

The animal feed production market will only get bigger over the coming decades – that’s what global trends show. What’s also clear is that the industry will have moved towards more sustainable production methods and engaged heavily in alternative ingredients to fill an increasing supply gap for protein feedstocks. This is already happening, but how much of an impact sustainable production method will make will depend on the level of adoption and the willingness of all stakeholders to engage.

Given the importance of customers as stakeholders, the current lack of transparency associated with food sustainability should be considered a significant problem. Improving general communication and clarity of the carbon intensity and ecological effects of the food on shelves would be a starting point for giving the public a voice in this conversation. To get there, we need a better shared understanding of measuring sustainability. There are increasing ways of calculating sustainability, and certain industries are better at it than others. Stronger regulations for undertaking life cycle assessments of the feed used in food and identifying the entire life cycle of products on the supermarket shelf would be a great start.

This article was first published in Feed & Additive’s Alternative Proteins special edition in April 2023.

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