Biological reactor for growing algae

In 30 years, global agriculture will have to feed 10 billion mouths - and do it without harming the environment. Should we look for the answer to these two problems under the light of the flashlight?
Ran Ben Michael, Angle - Science and Environment News Agency

In recent years, researchers and scientists have been trying to find a complete and satisfactory solution to two main problems in the agricultural sector: the damage caused to the environment as a result of agriculture (pollution, depletion of water and soil resources, damage to biodiversity, and greenhouse gas emissions that exacerbate the climate crisis) and the difficulty that is expected to arise in the not-so-distant future in feeding the world's growing population.

New agricultural applications (such as biological control), integrated production systems (such as urban agriculture or agriculture within forested areas), or genetic intervention in cultivation (for example, pest-resistant varieties) have contributed to the increase in agricultural yields, but these are often partial solutions and even cause controversy. The criticism revolves around the very success of the change (achieving an improvement in crops or nutrition) or around the fear - which is usually not based on facts at all - of a negative environmental impact as in the case of genetically modified varieties (GMO).

Nor have systemic changes, such as organic agriculture or agro-ecology, gained a significant hold on global agricultural production, even though their environmental impact is much smaller. In organic farming, the main reason is lower production per unit of area and a high and unsustainable price of the produce compared to conventional farming, and on the other hand, many farmers are still hesitant to integrate the methods of agro-ecology in their crops. Even if the application of both expands significantly while reducing the environmental footprint of agriculture, this will likely not allow the sustainable production of enough food while maintaining the economics of growth for farmers to feed a population that will reach almost ten billion people in 2050. Solutions that will bring about a revolution will probably have to come from outside the box.

"It is difficult to see how the conventional agricultural solutions will lead to a fundamental change in dealing with the food crisis," says Dr. Assaf Tzhor, formerly responsible for strategy and sustainability at the Ministry of Environmental Protection. Today Tzhor directs food security research at the Center for Existential Risk Studies and is a faculty member at the Center for Global Food Security of the University of Cambridge there seeks to find innovative and ground-breaking solutions that can really change the situation. "The current conventional solutions do not We are dealing with the ultimate limiting factors of agricultural production: a finite and absolute supply of fresh water and fertile soil."

Minimalist farming

According to Tzahor, to achieve a dramatic change in agriculture in the face of the climate crisis, three main challenges must be addressed: First, a crop must be found that will successfully complement the main agricultural crops: wheat, corn, rice, and soybeans, so that it overcomes the limitations of production resources, diversifies the nutritional values, including added protein, does not rely on the limitations of genetic engineering, and most importantly, its large-scale cultivation will not harm the environment. Soybean farming, for example, is a major factor in the clearing of the Amazon rainforest, partly because of its role in domesticating animals for the meat industry. Second, productivity must be improved – in plant crops, this means interfering with the photosynthesis process (in Hebrew, assimilation) – while overcoming the factors that limit it: the availability of light, water, fertile soil, and carbon. And third, this must be done in a sustainable manner, meaning relying on energy from a renewable energy source that does not emit pollutants and greenhouse gases into the atmosphere.

Sunlight is a powerful engine, but the rotation of the Earth, weather, cloudiness and shade limit its reach to plants: improving the natural efficiency of the photosynthesis process is a necessary move to increase agricultural productivity: the RIPE project at the University of Illinois seeks to increase this efficiency through genetic intervention.

However, light is the limiting factor that is relatively easy to overcome by other means: the recent years of cannabis becoming legal (in some places) and an available medicinal substance promoted the use of artificial light - LED lighting which is efficient and economical - in closed habitats. Fresh water makes up only 3 percent of the water on Earth and is a depleting resource, brackish and brackish water, on the other hand, is available almost without limit. A third limiting factor is fertile soil, but the agriculture of recent years has shown that it is possible to grow successfully in hydroponic or aeroponic cultivation, when the roots of the plant are immersed in water or exposed to the air (respectively), without any substrate.

Microalgae, of which tens of thousands of species are known to science, are organisms that can thrive in exactly these conditions: constant light, brackish water and independent of fertile soils. Algae have many uses (such as food and nutritional supplements for humans, cosmetics, color pigments, medicines, etc.) and they can also be used as an excellent food source for cows, pigs, poultry and fish in aquaculture (including the use of algae to feed carnivorous farming fish) and to replace a certain percentage (usually) These are individual percentages between 10-1 percent of the food, depending on the type of algae and the type of animal) from the sources of protein, carbohydrates and fat of those animals.

Tzhor and his team wish to propose an alternative design of a food production system based on a combination of four technologies and recently published their findings on what appears to be an interesting solution to create food for industrial use based on algae and with minimal negative environmental effects, and perhaps even the opposite.

200 times more effective

This solution is found in Hangil in Iceland where four relevant technologies are combined for an innovative and unique move: growing algae in photobioreactors - closed and controlled growing systems (led by another Israeli researcher, Dr. Yitzhak Barzin); capturing carbon from the atmosphere by a Swiss company; advanced LED systems; and producing renewable energy from a source Geothermal Algae is the agricultural crop that, according to researchers, can be a substitute for some of the main crops As food for animals or humans, carbon capture and lighting technology provide the main inputs to the photosynthesis process and this type of renewable energy ensures that the production process will have a small carbon footprint. Beyond that, brackish water is needed, which is a scarce resource and few nutrients.

The combination of these four technologies creates what is known as a "biological reactor". Similar to a nuclear reactor where the process of splitting atoms produces energy over a long period of time, here non-perishable inputs produce a product: plant food for animals with high nutritional values. Unlike a nuclear reactor, this process can go on almost indefinitely and more importantly, even if you take into account the life cycle of the entire system and its ongoing energy consumption, its environmental footprint is still positive.

"When you look at the food production system created by combining these four technological platforms, you get a system that is almost 200 times more efficient than the use of land and water in normal open systems or traditional agriculture in the field," says Tzhor. "Furthermore, we are very optimistic about the system's ability to grow from its current experimental scale to large-scale production." The production capacity of the system is estimated at 86,000 tons of dry matter per square meter (compared to approximately 400 tons in a conventional soybean field); this production capacity can be aimed at different types of algae, those that are part of the food mix of the IDF (such as those produced in today) or human nutrition (like spirulina) and can enrich them with amino acids, fatty acids and omega 3 or 6.

The potential for growing agricultural crops that require little resources to grow must be realized under appropriate conditions - mainly through the use of renewable energy sources and the need for the availability of brackish water - and it is not suitable for every place; "Therefore, Israel is not the natural candidate for implementation in the near future," says Zachor, "mainly because its energy mix is ​​mainly based on depleting and polluting sources. Unfortunately, the energy economy limits the food economy." It may be that the implementation of the experimental system, which still needs to go through a phase of upscaling, will not be economical for certain types of agricultural farms (for example in developing countries) due to their size, transportation to distant places, and the like.

Tzhor and his research partners believe, however, that the overall contribution of implementing such a system, where the food produced is superior from the environmental and health aspects, is the most promising move.

More of the topic in Hayadan:

• Where does the algae go after they die?
• The dangers of global warming - the seaweed farming industry in Zanzibar
• Questions for the future of humanity: What geological imprint will we leave behind?