Mould-fighting yeast revolutionary for grain producers

An accidental discovery by Swedish researchers could revolutionise the storage of grain in tropical environments.

When conducting a bio-control study, researchers noticed that one particular silo of grain did not have any mould growing on it. On closer inspection, they noticed a multitude of tiny white dots growing all over the grain. 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 at the Swedish University of Agricultural Sciences have been a success and, along with the help of Swedish company Jästbolaget, the researchers are now trying to develop the system into a large-scale publicly available product.

“It is really quite a simple process,” explains Matilda Olstorpe, the project coordinator. “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 system has potential to significantly benefit grain producers in tropical regions of Africa, where the moist air alone can propagate the growth of moulds. 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,” said Olstorpe.

The yeast has also been shown to have a much higher protein content than any of the other yeasts examined. “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.

Development of the product has not been without problems. The yeast is difficult to grow on a large scale, but the researchers are confident this can be overcome.