Application of Algae in Food Technology
Introduction
The current sustainable development goals by the UN include abolishing world hunger and sustainably exploiting the world’s oceanic zones.According to the latest World Population Data Sheet from the Population Reference Bureau,recent estimates indicate an increase in world population to roughly 9.9 billion people in 2050. This means there is an urgent need for more sustainable food sources that meet these climate targets, whilst feeding a growing population.
Among many of the food solutions being currently investigated to feed the growing population, algae remain an exciting crop with a wide range of applications in Food Tech and Biotech.
Broad definition of micro- and macroalgae
Algae are photosynthetic organisms ubiquitous to marine habitats throughout the world. These organisms are a diverse polyphyletic group, meaning that algae are not restricted to a single phylogenetic classification, but are instead spread in different groups. Algae can be broadly characterized as microalgae, which are unicellular organisms with diameters in the microscopic range, and macroalgae or seaweed, which are larger, multicellular organisms with sizes ranging from a few centimeters to hundreds of meters.
In addition, macroalgae are usually categorized as: Brown (Phaeophycea), Red (Rhodophyta), or Green macroalgae (Chlorophyta).
On the other hand, microalgae are usually split into green microalgae (Chlorophyta), red microalgae (Rhodophyta), Stramenopiles from different classes such as diatoms (Bacillariophyceae) and Nannochloropsis (Eustigmatophycea), haptophytes (Haptophyta), and dinoflagellates (Dinophyta) (Heimann & Huerlimann, 2015).
Moreover, Cyanobacteria, or blue-green algae, are also photosynthetic but more closely resemble bacteria since they are prokaryotic organisms, while microalgae are eukaryotes (Martínez-Francés and Escudero-Oñate, 2018).
Environmental advantages of algae as biomass for food applications
The rationale behind using algae as sustainable biomass for food relies on the fact that algae are photosynthetic organisms that capture carbon from the environment and do not require arable land for production. For instance, macroalgae aquaculture can contribute to carbon sinking while oxygenating the waters and reducing ocean acidification and macroalgae are low-carbon footprint foods (Duarte et al., 2017). In addition, microalgae photobioreactors can be set in arid terrains that do not support agricultural venues. Microalgae can be used as a protein source but also as a more sustainable platform for omega-3 fatty acid production than aquaculture fish, according to a recent life cycle analysis (Schade et al., 2020). While this study reported different carbon emissions depending on the microalgae production platform, it was shown that microalgae-based production of fats had a lower global warming and acidification potential than most fish except for wild herring and cod or aquaculture carp (Schade et al., 2020).
General description of commercially valuable micro- and macroalgae
According to a recent document by FAO (Food and Agriculture Organization), the production of aquaculture-based algae has reached 32.4 million tonnes in 2014, with a farmgate sale value of USD $ 13 billion (FAO, 2020). Most aquatic seaweed production is primarily performed in Asia, and Japanese kelp is the species carrying the highest global production, at 11.4 million tons (FAO, 2020). Even so, algae production is spanned throughout the globe, and the top exporters in 2020 can be found in the graph below, which was put together after accessing the market analysis platform Tridge.
Interestingly, while looking through Tridge’s data on global imports, the US comes up as the second largest importer of seaweeds with an import value of USD $57.1M in 2020 and a market share of 15.65%, only topped up by Japan which imported a total value of USD $204.7M in 2020 and had an import share of roughly 56% of the global seaweed import market, as can be seen in the following scheme.
Shematic representation of global seaweed importers in 2020. Adapted from www.tridge.com
Microalgae are also used in various food applications. For instance, the green microalgae Chlorella vulgaris (Chlorophyta) is used as a dietary supplement, Dunaliella salina is a common beta-carotene source and the dinoflagellate (Dinophyta) Crypthecodinium cohnii is used as a docosahexaenoic acid (DHA, one omega-3 fatty acid) source for enrichment of infant formula (Heimann & Huerlimann, 2015). Furthermore, the cyanobacteria Spirulina is also produced already throughout the world for food consumption and nutritional supplementation (Araújo et al., 2021; FAO, 2020), since it has high protein content and is a source of multiple vitamins and polyunsaturated fats (see the review from Araújo et al., 2021).
Retail prices for macro and microalgae, as well as cyanobacteria, are dependent on many factors, including the production method, if the biomass is sold in dry weight, and differs among species (Araújo et al., 2021). From a quick look into bulk seaweed suppliers (such as the Chinese supplier Made in China, and the global goods suppliers Go4WorldBusiness), it appears that prices of common edible seaweeds also fluctuate according to the manufacturer’s geographical location as well as the total purchased amount.
Short overview of algae-based startup landscape
In addition to a blooming sector for whole algae biomass, there has been recent interest in using algae components to structure a plurality of food products, such as plant-based meats. For instance, the health food brand Damhert has announced it is rolling out microalgae burgers in Belgium and The Netherlands. Meanwhile, Ireland’s Plantruption is releasing its seaweed burgers, allegedly with a complete nutritional profile that includes 30g of protein per serving, as reported to Vegconomist.
Companies exploring microalgae ingredients include Sophie’s Nutrients, which aims to produce microalgae protein powder from food and beer side streams to sell to B2B partners for plant-based foods. Another promising startup that plans to produce components for plant-based foods include US-based Triton Algae Innovations, which aims at producing heme iron, which is a critical flavor compound from meat, in microalgae without genetic modifications.
Microalgae and Cyanobacteria
Sourcing ingredients and current cultivation methods
Microalgae are primarily cultivated in terrestrial lands, and both photobioreactors (PBRs) and open ponds are two major cultivation methods. In the case of algae cultivation dependent on light (i.e., photoautotrophic algae), the main hurdle into establishing current systems relies on light limitations in certain geographical regions, as well as the lack of larger systems for scaling up production (Araújo et al., 2021).
As an example, PBRs are the main microalgae cultivation method used in Europe, but companies exploring the production of Spirulina usually do so in Open Ponds (Araújo et al., 2021)
Production prices are influenced by the chosen cultivation type, and open ponds are usually the least expensive cultivation technique, when compared with tubular or flat panel photobioreactors (Spruijt et al., 2015). However, they are more susceptible to contamination and could require higher inputs of land and water (reviewed in Araújo et al., 2021). In addition, a plurality of other factors impact the cost of a microalgae production facility, such as land use, labor, wastewater treatment, capital goods, water inputs, and electricity (Spruijt et al., 2015), and the cost of these inputs can be largely optimized.
Application of microalgae in plant-based meat and fish
Microalgae can be used to produce plant-based foods as whole biomass or only utilizing specific fractions, such as those containing protein, polyunsaturated fats, vitamin A and C, and pigments such as beta-carotene (Martínez-Francés and Escudero-Oñate, 2018). In addition, flavor compounds that improve the palatability of plant-based alternatives to meat and fish are also promising constituents of microalgae biomass. For instance, one of Triton Algae Innovation’s approaches relies on accumulating heme in green algae Chlamydomonas reinhardtii using UV at selected wavelengths. Hence, by not depending on genetically engineered organisms, Triton’s technology could assure its application in food products throughout markets with restrictive legislation regarding GMO use in foods.
Another promising feature of microalgae is their ability to accumulate vitamin B12 in certain conditions. Some Chlorella powders already contain residual concentrations of this vitamin, though most microalgae contain pseudocobalamin (Edelmann et al., 2019). Furthermore, some microalgae might be able to remodel pseudocobalamin generated by cyanobacteria or bacteria into bioavailable vitamin B12 (Tandon et al., 2017, Grossman, A, 2016). However, most B12 uptake by algae is thought to arise from bacteria (Croft et al., 2005). Therefore, there have been recent efforts into optimizing microalgae uptake of Vitamin B12 from bacteria that produce it, for instance via co-culturing systems (Pereira et al. (2019)
Application of microalgae in Cell Ag
A recent article has shown that amino acids and glucose sourced from microalgae can be used as cell culture medium components (Okamoto et al., 2018). Similarly with plant-based foods, microalgae are valuable sources of lipids (Martínez-Francés and Escudero-Oñate, 2018) which could also be used in medium supplementation in cellular agriculture, as well as post-processing addition to improve the nutritional profile of a given cultivated meat or fish product. Other microalgae, for instance certain species of Chlorella and Scenedesmus, are also a source of vitamin A and C (Martínez-Francés and Escudero-Oñate, 2018)
Using microalgae as platforms to produce flavor compounds such as heme, like Triton’s approach, might also allow its application in cellular agriculture, should there be the requirement to improve the organoleptic properties of certain products.
Hypothetical applications of microalgae in cell ag include using its protein and polysaccharide composition to produce scaffolds for cell culture, as well as using microalgae as recombinant platforms for high-value molecules, such as growth factors, if they outperform current strategies, which are mostly based on bacteria and yeast.
Macroalgae
Current cultivation methods
Traditional seaweed farming has occurred mostly on the coastlines, though most macroalgae are currently farmed offshore, and an additional 1 million tons come from wild-caught populations (see review from Ullmann and Grimm, 2020). Macroalgae can also be cultured alone or in combination with other animals (such as fish and crustaceans) in what are termed multi-trophic aquaculture systems.
Opportunities for plant-based and fermentation-enabled foods
Much like microalgae, macroalgae is also a source of amino acids and healthy nutritional fats (Wells et al., 2017) that can be used in plant-based food formulations. This crop has productivity akin to terrestrial plant crops, and an offshore farm in Japan can produce 1.3 kg of kelp Laminaria angustata in one square meter (Ullmann and Grimm, 2020).
Among the many compounds that can be extracted from algae, antioxidants like β-carotene, astaxanthin and vitamins (such as A, C and E) (Wells et al., 2017) can be also added to plant-based formulations to improve the nutritional profile of these foods.
Furthermore, algae are a source of minerals such as calcium, iron and magnesium, although its composition is variable across species, and in certain stances macroalgae accumulate high amounts of minerals that restrict their consumption as whole-foods (Circuncisão et al., 2018). Nonetheless, these algae are still a promising source of minerals to improve the nutritional balance of plant-based meats, fish and beverages intended to mimic dairy products. In fact, red macroalgae Lithothamnium calcareum is already used as a calcium source in plant-based milk from the brand Provamel.
In addition, certain macroalgae such as Nori are also a source of Vitamin B12 (Croft et al., 2005) and species like Nori can be used as biomass to produce Vitamin B12-containing plant-based foods.
Opportunities for Cell Ag
As with microalgae, the protein content of seaweeds, as well as their fats and vitamins, could be used for cell culture. However, at the time of writing this post, no article about it was found.
Hydrocolloids from macroalgae that have been extensively used in the food industry include carrageenan and alginate, which both could have promising applications for cultivated meat and fish companies.
Carrageenan is an interesting material as a scaffold to grow cells using the material by itself (Rode et al., 2018) or in combination with other polymers (Pourjavadi et al., 2019; Lim et al., 2010), both in cellular agriculture and as a plant-derived material for tissue engineering applications. Algae like Irish moss were initially used in carrageenan production (Collén et al., 2014), but can be extracted from other algae. Thus, carrageenan extraction and sales can represent a major revenue stream for different applications, including food and biotech research.
Similarly, alginate is already used as a scaffold with multiple applications in tissue engineering, and cell ag researchers have also been briefly accessed and published on the growth and proliferation of bovine fat precursor cells (Mehta et al., 2019).
Future outlook
Overall, microalgae and seaweed have enormous potential for food applications, as an established safe source of various nutrients that can be harvested in potentially more sustainable ways than other industrialized foods.
Even so, the cost of producing microalgae still requires further optimization, which can also be expected to occur while companies manage to scale their production. Like most industrialized food technologies, the price of microalgae production is largely impacted by scaling up. For instance, one monograph describes open pond cultivation systems for bioenergy applications, and mentions that the price per kg of dry microalgae is roughly 35€ if 1 open pond of 1000m2 is operating, while 100 of these same ponds reduces the cost to roughly 9€/kg, and could decrease to roughly 6€/kg if 1000 identical open ponds are used (Spruijt et al., 2015).
In addition, the economic feasibility of macroalgae cultures is largely improved if there is side stream upcycling of bioactive materials that remain after extraction of other target compounds (Rotter et al., 2021). Hence, investors and startups that want to participate in the industry as biomass or extract providers should carefully plan additional revenue streams from the production of these photosynthetic organisms, to improve their profitability.
Written by Gonçalo Fernando for Helikon Consulting
