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Journal of Lipids
Volume 2018, Article ID 5325804, 8 pages
https://doi.org/10.1155/2018/5325804
Research Article

A Fast and Simple Qualitative Method for Screening Oleaginous Yeasts on Agar

1Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco A.C. (CIATEJ), 800 Normalistas Av., 44270 Guadalajara, JAL, Mexico
2Cátedras CONACYT- Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco A.C. (CIATEJ), 800 Normalistas Av., 44270 Guadalajara, JAL, Mexico

Correspondence should be addressed to Georgina Sandoval; ten.aicneulfnoc@lavodnasg

Received 22 March 2018; Revised 19 June 2018; Accepted 4 July 2018; Published 29 July 2018

Academic Editor: Difeng Gao

Copyright © 2018 Xochitl Niehus et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Finding new oleaginous yeasts is of great interest due to their many important applications. Currently available screening procedures are time-consuming, and most of these require liquid cultures. In this work, a new, fast, economical, and simple qualitative method for screening oleaginous yeasts was developed. The fluorescent dye, Rhodamine B, was selected because its fluorescence is directly correlated to lipid content, and no additional steps or special equipment are needed. This method only requires growing the yeasts on dyed agar plates. Under visible light, it is easy to observe that nonpigmented oleaginous yeasts become colored, whereas non-oleaginous yeasts remain uncolored. The developed method is also useful for improving medium composition in specific applications. Moreover, it was also adapted to use alternative carbon sources, such as lignocellulosic materials and glycerol. The developed method was applied to screen 124 recently isolated nonpigmented yeasts on three different carbon sources, namely, glucose, glycerol, and agave bagasse hydrolysate. Five strains were selected as good lipid producers on all tested carbon sources and accumulated over 48% lipids. Furthermore, the assay was adapted to screen reddish-pigmented yeasts. Considering all the above, the developed method has a wide range of applications in the field of microbial oils.