New Scientist article 1 of 2 Next Previous work has identified an enzyme that helps the oils to convert starch to oil, allowing them to be refined into edible oils and fats.
But until now, scientists had not been able to figure out how to make grapeseed and olive oil from the same substance.
“We have to figure what’s going on in the plant,” says Dr. Peter Senn, a chemist at the University of Oxford in the UK, who led the study.
It turns out that one of the enzymes involved in the process is also used to break down plant materials, such as the oils that we commonly use for cooking and baking.
The enzyme, called an amylase, is found in the same plant as the enzyme that breaks down the starch found in wheat, and also the starch used to make potato starch, so it is not surprising that it is used to digest the same stuff.
“I am a bit surprised that it does not work in the plants we know so well,” says Senn.
In fact, Senn says, his team is investigating the chemistry of the amylases in plants that are currently being grown in Europe and elsewhere, as well as the potential role that these enzymes play in making synthetic polyunsaturated oils and fuels.
“There’s lots of work being done on polyunsaturates,” says Maren Kostner, a bioengineer at the Technical University of Munich in Germany who was not involved in this study.
But it’s still not clear what, if any, of that work will lead to better polyunsaturation.
Senn’s team has previously identified a similar enzyme in the yeast Saccharomyces cerevisiae that is used by microbes to break apart the starch in the grains used in bread, which they have shown could be used as a starting point for making synthetic oil.
“It’s very exciting to see that we can combine these two reactions in the bacteria,” Senn explains.
It’s a way to make plants use the same chemical process for making the same kind of material.
“That would be an amazing breakthrough,” says Kostter, who was also not involved.
“But it’s also very, very hard to translate this into an efficient process,” she adds.
“Even with this new knowledge, you still need to figure how to grow these plants.”
Senn has previously discovered that the amytases in grapeseed are not unique to the plant they’re from.
“Grapeseeds have many amylas that are present in other crops, including corn, and they are also found in other plant parts, such a leaves, and we know that this is what happens when these enzymes are used,” he says.
This suggests that the enzymes are part of a system that is present in the environment, and it is possible that the molecules found in these other plants could be made from grapeseed.
“This is a very exciting discovery,” says Joris Geurts, a synthetic biologist at the Max Planck Institute for Evolutionary Anthropology in Germany.
“They’re very different enzymes and they’re all related to one another.”
Geursts and Senn also think the amo-based compounds are also similar to the chemicals used in natural food processing.
“If you think of the chemical components of sugar in the foods we eat, then we would expect to see similar enzymes that are used in food processing, in addition to these enzymes that we find in these plants,” Geurbs says.
“In other words, we’re finding this kind of a natural food analogue in the soil that is not natural.”
But Senn cautions that this study does not rule out the possibility that the sugars found in grapeseeds may be produced in other ways.
He also says it will be important to investigate the possibility of using these enzymes to make synthetic polymers.
“Because the enzymes they are working with are in the gut, they might be able to make plastics and plastics-like materials that can be processed and then later reused,” he explains.