Engineered Lipase Cuts Out Trans Fats

Biochemists led by Uwe T. Bornscheuer of Germany’s University of Greifswald have engineered the first enzyme capable of selectively hydrolyzing unhealthy fatty acids from triglycerides in partially hydrogenated vegetable oils. The development could lead to a new industrial food process. In 1901, German chemist Wilhelm Normann invented the catalytic process for hydrogenating double bonds in the fatty acid chains of vegetable oils. Modifying the oils helps prevent them from turning rancid and raises their melting points so they can be handled as solids. But there was an unforeseen catch: Trans fatty acids, a by-product of the hydrogenation process, are now known to be a risk factor for heart disease, obesity, and other health problems. Food processors have responded by chemically reformulating their products to reduce trans fat content. In a different approach, Bornscheuer’s team created a variant of a fat-cleaving lipase, originating from the yeast Candida antarctica, and expressed it in Escherichia coli using a new protein-engineering strategy combined with high-throughput enzyme screening (Angew. Chem. Int. Ed., DOI: 10.1002/anie.201106126). The variant selectively hydrolyzes trans and fully saturated fatty acid chains; the cleaved unhealthy fatty acids can be separated from the remaining mono- and diglycerides in the vegetable oil.