The unicellular fungus Ustilago maydis (left: microscopic image) is the pathogen that causes the plant disease corn smut (right: image of a plant with the disease). The fungus can be genetically modified to produce a microbial oil. Credit: HHU / Magnus Philipp
Palm oil is one of the most widely used vegetable oils in the world, serving as a low-cost ingredient in many sectors of the food industry as well as a component in the production of biofuels. However, palm oil production raises many ecological concerns, as large areas of tropical rainforest have been cleared to enable the planting of palm tree monocultures; additionally, palm oil produced in the tropics must be transported long distances to consumers in Europe and the US. The Bioeconomy Science Center-funded research consortium NextVegOil, which includes researchers from HHU Düsseldorf, RWTH Aachen, the University of Münster and Ruhr University Bochum, now aims to produce a local, sustainable palm oil substitute from corn waste, by harnessing the corn-recycling abilities of the unicellular fungus Ustilago maydis.
U. maydis is typically seen as an enemy in agriculture because it causes a plant disease called corn smut. However, the fungus is harmless to humans and even considered a delicacy in Mexico. The research aims to use the fungus’ affinity for corn as a positive, as the organism is ideally suited to recycle corn residues, said Michael Feldbrügge, a research group member from the Institute of Microbiology at HHU. The team has already engineered a variant of U. maydis that can produce a microbial oil remarkably similar to palm oil in its fatty acid composition. This fatty acid profile can be further varied by adjusting cultivation parameters and through additional genetic modifications to U. maydis. While the fungus has already been used in the production of other biotechnologically relevant substances, like biosurfactants, the researchers have demonstrated that interrupting the synthesis process at the genetic level leads to the production of oil, rather than surfactant.
A major goal of the product is to establish a method of using the fungus to ferment corn stover on a large scale. This could have additional economic benefits as corn stover is a waste product that cannot otherwise be eaten or even used as animal feed. Additional work will focus on optimizing U. maydis to produce oil that more closely matches the properties of palm oil. Once the optimum parameters for the corn biomass conversion and fungus have been found, it will be possible to move on to implementing the fermentation process on a commercial scale. The oils produced in this microbial process must then be precisely analyzed and purified to ensure they meet food standards. Additional information about NextVegOil can be found on the Bioeconomy Science Center website.
“It is important to everyone involved in the project that we can offer a sustainable product as an alternative to conventional palm oil: a regional product, made from renewable raw materials, with a good carbon footprint. And also a product which does not compete with food production, as the starting materials are residues that are generated anyway.” Feldbrügge and Markus Pauly, from the Institute of Plant Cell Biology and Biotechnology at HHU, said in a statement.
If commercial-scale production of the palm oil substitute is successful, the consortium plans to demonstrate the economic benefits of their method in partnership with biotech start-up Formo, which aims to produce vegan cheese using the substitute.