Stored grain does not need to be kept in dry conditions – a huge benefit for agriculture in humid countries

The Swedish University of Agricultural Sciences has been working on a system that uses a specific strain of yeast to greatly improve the resilience of harvested crops to mould. The new grain storage system could cut the energy intensive process of drying the grain out of the equation

The discovery was made by chance when, as part of a bio-control study, researchers noticed that one particular silo of grain did not have any mould growing on it. After closer inspection of the grain, they noticed a multitude of tiny white dots growing all over it, and so took a sample of the mysterious substance. Subsequent analysis showed it to be a strain of yeast that was producing large quantities of the substance ethyl acetate, which was inhibiting the growth of mould.

Initial trials of the new system in Sweden have been a success and, along with the help of Swedish company Jästbolaget, Matilda Olstorpe, the project coordinator, is now trying to develop the system into a large-scale publicly available product. “It is really quite a simple process,” explains Olstorpe. “You take the grain, or whatever it is that you wish to preserve, and you inoculate it with the yeast before placing it in the storage system. There is then no need to even dry the grain, so it can be put into storage straight from the field while still quite wet.”

The benefits of using this system in tropical regions of Africa could be huge. Growing enough grain to feed an expanding population is already a big problem, but storing it long enough for it to be used is also an issue. With some areas having two rainy seasons a year, the air is often so moist that this alone can propagate the growth of moulds on grain. Couple this with small scale drying techniques that introduce other toxins into the grain, and the impact that this new storage system could have suddenly becomes obvious. A project has now begun in Cameroon, carrying out pilots of the system to see if it can work effectively in the field. “We want to teach people to maintain their own cultures of the yeast, so they can use it as and when it is needed,” says Olstorpe.

The yeast has also been shown to have a much higher protein content than any of the other yeasts Olstorpe has looked at. “It thus has the potential to be an excellent single cell protein source, and also adds nutritional value to the grain that we put it in,” says Olstorpe.

Despite the plethora of beneficial attributes associated with the microorganism, development of it as a product has not been without its problems. One drawback encountered is that it is quite hard to grow on a large scale. “However, this is more of a technical problem and is not something we cannot overcome,” explains Olstorpe. In a world where resources are becoming scarcer and the cost of wasting them is getting higher, the potential of this microorganism is huge.