Browsing by Author "Arcos Velasco, Lizeth Vanessa"
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Item Selección y caracterización de levaduras oleaginosas aisladas a partir de sistemas acuáticos de la ciudad de Cali(Universidad Santiago de Cali, 2020) Arcos Velasco, Lizeth Vanessa; Ramírez Castrillón, Mauricio (Director); Osorio Cadavid, Esteban (Director)Yeasts have been reported as a source of microbial oil of industrial interest, since the accumulation and lipid profile of each strain can present potential use as a raw material for the generation of biodiesel (monounsaturated fatty acids) or food (polyunsaturated fatty acids). Furthermore, oleaginous yeasts represent a promising option for this purpose, because they accumulate neutral lipids, mainly triglycerides, in a high proportion of biomass (20%-70%, w/w). So, the objective of this project was to evaluate the lipid accumulating capacity in a yeast collection previously isolated from aquatic systems in Cali, Colombia. 25 strains were analyzed to determine their possible oleaginous nature and a lipid production screening was performed by gravimetry (weight of total lipids with respect to their dry biomass), being selected the yeasts with higher percentage of lipids. These strains were identified at the species level using ribosomal regions sequencing and were compared with the sequences of type strains deposited in the Genbank and Mycobank databases. Five strains of yeasts with a yield of 20% g/g or more were selected for lipid production.Item Tropical lakes as a novel source of oleaginous yeasts with lipid profiles for biodiesel, oleochemical, and nutraceutical applications(Springer Science and Business Media B.V., 2025-03-13) Ramirez Castrillon, Mauricio; Benavides León, Tatiana Andrea; Arcos Velasco, Lizeth Vanessa; Pantoja Pulido, Kriss Dayana; Lopez Parra, Lizbeth Lorena; Bolaños Rojas, Ana Cristina; Osorio Cadavid, EstebanOleaginous yeasts have emerged as promising microbial cell factories for lipid production, offering sustainable alternatives to traditional sources of biodiesel and nutraceuticals. In this study, the lipid accumulation potential of yeast strains isolated from two freshwater aquatic ecosystems in Cali, Colombia, was evaluated to identify novel candidates for biotechnological applications. A total of 56 strains were tested for their oleaginous nature using a gravimetric lipid assay with glucose as a carbon source. Of the assessed strains, 46.15% exceeded 20% lipid yields relative to the dry biomass. Seven strains were selected using glycerol as a carbon source, but only five yeasts were further characterized for their lipid profiles. Molecular identification revealed diverse species, including Aureobasidium sp., Papiliotrema rajashtanensis, Rhodotorula spp., and Clavispora lusitaniae. The selected strains demonstrated unique lipid profiles, with high proportions of monounsaturated and polyunsaturated fatty acids, such as oleic acid (C18:1) and linoleic acid (C18:2). In particular, Aureobasidium sp. accumulated uncommon fatty acids such as petroselinic acid under conditions induced by glycerol. This fatty acid, which has a double bond in position 6,7 and a melting point of 33 °C, highlights its potential as an alternative to margarine production, as well as a precursor to sophorolipids, estolide esters, soaps, and plastics. Rhodotorula sp. exhibited very long-chain fatty acids such as docosadienoic and docosatrienoic acids in its lipid profile. These findings underscore the biotechnological value of yeasts from lentic aquatic systems as sustainable lipid producers, paving the way for innovations in biofuels, nutraceuticals, and oleochemicals.