Farming in cities could help feed the world

If climate change begins to limit the global production of food and energy crops, it will be necessary to develop a new system of food production.

Imagine agriculture in small spaces, using high-tech tools such as photo-bioreactors, generating clean products 24 hours a day, every day, regardless of external climatic factors. Imagine that this would be free of pathogens and agrochemicals, independent of the seasons, and with the possibility of growing genetically modified crops without interacting with the environment or affecting existing biodiversity.

This is “urban biofarming”, a kind of high-tech agriculture primarily developed for big cities.

Food production and food security were under threat from urbanisation and population growth even before the prospect of a global climatic catastrophe. With this in mind, we at the University of Antioquia in Medellin, Colombia, have been conducting a series of investigations into differentiated cell and tissue culture for the cultivation of future food and energy products.

So far, our work has focused on using cell culture to produce cocoa, the oil of the Barbados nut Jatropha curcas, and orange juice. Other plant species in the pipeline include sugar cane, corn, wheat and barley. These efforts could be a milestone in demonstrating the feasibility of urban biofarming.

Limits to genetic modification

One solution to the potential failure of conventional agriculture is genetic modification, which can make crops resistant to environmental extremes, such as droughts or floods.

However, it is unrealistic to expect this to be developed for every kind of food. This would require huge financial resources, lots of scientific research, and long periods of time for the crops to pass all the necessary biosecurity protocols before they can be planted in fields in direct contact with the natural environment. The crops would also need to adapt well and have high enough yields to feed the world.

Genetically modified organisms face another obstacle: they are the focus of considerable social concern. We should really look elsewhere for the answer.

The alternative could be plant biotechnology - specifically, the in vitro culture of cells and tissues of edible parts of certain crops or fruit. As yet, however, there is little scientific literature on such research.

Cell culture also allows the synthesis of new natural products, makes it possible to create “bio-factories” to convert low-value crops into high-value products and generates new compounds not normally produced under natural conditions. You can generate new products that do not exist in the market today - for example, mixing cocoa cells with almond cells to generate a cocoa-almond taste product. You can also induce the cells by using compounds called precursors to produce other new compounds by way of biotransformation.

Commercial production

The use of cell culture has already had a big impact on research in physiology and biochemistry, especially in studies of cellular metabolism and work to determine the effect of substances such as plant hormones on cellular responses.

In genetics, cloning has allowed the improvement of cell cultures through the fusion of protoplasts - plant cells from which the cell wall has been removed - and genetic transformation. Progress has been so good that with modern techniques it is now possible not only to culture free cells, but also to allow cell division in an isolated culture and use this to grow whole plants.

Additionally, the in vitro culture of cells suspended in liquid provides a system for the commercial production of a large quantity of plant products known as primary and secondary metabolites.

If these production systems are stable and competitively priced, they can potentially be scaled up for commercial and industrial use.

Crop production of this sort could help preserve biodiversity, since you would not need more land or forest destruction for agriculture, would use less water, and avoid using up primary land. It could be implemented anywhere on the planet, and even in space.

Cell and tissue culture have the potential for both basic research and applied research to develop industrial products, such as fragrances, dyes, gums and resins, especially for countries such as Colombia that have considerable plant biodiversity. But they are rarely implemented in these countries - most of the research is carried out in developed countries with relatively little biodiversity.

Biodiversity is important here because cell culture aims to reproduce the original, parental material, so this needs to be of sufficiently high quality. Any plant parts used for tissue culture must also be of similarly high quality.

Cost concerns

Most of the existing research in this field focuses on the production of secondary metabolites, partly because traditional agricultural systems are widely seen as being more economically feasible and secure for food production. But climate change could swing the balance towards cell culture.

The high cost of cell culture is largely attributable to the technological tools it requires, so at the moment it is not really feasible for developing countries to produce their food in this way. But as so often happens with technology, once it gains popularity and becomes widely used, competition soon drives the price down.

It seems, though, that there has never been a thorough cost analysis of the whole process, from basic production through cell cultures to pilot industrial-scale production, with costs being evaluated at each stage.

When cell culture techniques have been properly costed in this way, they can be compared with conventional agricultural production of the same crop under natural conditions, and the environmental benefits can also be compared.

In 20 to 30 years this new production system could help to feed the world and give us opportunities to survive in the event of an environmental catastrophe.

But for that to happen, it must be implemented worldwide as soon as possible, so we can be prepared for whatever the future brings.