Maximization of microbial oil containing polyunsaturated fatty acid production by Umbelopsis (Mortierella) isabellina

Abstract

Abstract Filamentous fungi, such as Umbelopsis isabellina, produce oils rich in monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA), which are essential nutrients that regulate the physiological processes necessary for human health and development. Therefore, this study aimed to optimize the microbial oil production of Umbelopsis isabellina by maximizing lipid and PUFA production under different forms of cultivation. The best production conditions in shake flasks (250 mL) were evaluated by analyzing three different culture medium components (yeast extract, peptone, and sucrose) and three fermentation parameters (stirring rate, temperature, and pH). In this cultivation form, the optimal condition had a lipid yield of 31.77%, of which 16.68% were PUFA. Subsequently, to assess the best condition in a 2.5 L agitated tank bioreactor (STR), stirring and aeration rates were also evaluated using a central composite rotatable design (CCRD), and the optimized condition resulted in a lipid yield of 36.58%, of which 14.88% are PUFA. Fifteen fatty acids were identified, and the main ones (decreasing order) were oleic (47%), palmitic (27%), linoleic (11%), and γ-linolenic (5%) acids. The microbial oil produced has a good fatty acid profile with prominent presence of fatty acids of the n-6 family (linoleic and γ-linolenic acids), and also presence of n-3 family (α-linolenic (ALA), eicosapentaenoic (EPA), and docosahexaenoic acids (DHA)), demonstrating the potential of large-scale lipid production with great potential for use in developing food additives and nutraceutical ingredients.