Valorization of Oil Cakes in Two-Pot Lactone Biosynthesis Process

Oil cakes are biomass wastes created by pressing oil from oilseeds. Their chemical composition (including high fat or protein content, a favorable fatty acid profile, and a high proportion of unsaturated acids) makes them valuable raw materials not only in animal feeding but are increasingly gaining popularity in biotechnological processes. This article examines the possibility of valorizing oil cakes using the lipid fraction extracted from them or their raw form in a two-pot biosynthesis process of GDDL-a cyclic ester with a creamy-peach aroma. This study tested five types of oil cakes (hemp seeds, rapeseed, safflower, camelina, and flax), analyzing their physicochemical composition and the fatty acid profile of their lipid fraction. Due to the high content of oleic acid (over 62% lipid fraction) and the wide availability, rapeseed cake was used in the biotransformation process. The synthesis of GDDL involved a three-step process: hydrolysis of triacylglycerols, hydration of oleic acid (via lactic acid bacteria in anaerobic conditions), and β-oxidation (via <i>Yarrowia</i> yeast, aerobic process). The analysis showed that it is possible to produce because of the two-pot biotransformation of approximately 1.7 g of GDDL/dm³. These results highlight the process's potential and justify the feasibility of waste valorization. The proposed biotransformation requires optimization and is a good example of the application of the circular economy in food processing and waste management.