Selection of oleaginous yeasts isolated from sugarcane bagasse as the potential producers of single cell oils and other metabolites

PurposeThe microorganisms that possess diverse and improved traits for biotechnological applications provide an opportunity to address some of the current industrial challenges such as the sustainability of fuel energy and food. The aim of this study was to isolate and select the potential yeast isolates from sugarcane bagasse for single oil production.MethodsThe oleaginocity of the yeasts was confirmed through a gravimetric analysis of lipids, Nile red, sulfo-phosphovanillin (SPV) and a gas chromatography method for fatty acid methyl esters (FAME). The identification of the selected yeasts was carried out through a 5.8S of the ribosomal internal transcribed spacer (ITS) and 26S ribosomal DNA (rDNA) sequences. The carbohydrate and protein contents were estimated using phenol-sulfuric acid and hot trichloroacetic acid method, respectively.ResultsThe yeast isolates accumulated lipids of between 28% and 67% of the dry cell weight, and 22-33% based on the SPV assay, qualifying them as oleaginous yeasts. The selected yeasts were identified as Candida ethanolica and Pichia manshuriica. The lipids contained high levels of fatty acids in the following order: oleic acid, palmitic acid, stearic acid, and linoleic acid, which made up 82% of the total lipids.ConclusionAll the six selected yeast strains have the potential to produce single cell oils and other metabolites. The fatty acids composition of the selected yeast species was found to be suitable for the applications in biofuel, nutraceutical, and food industry. The yeast strains require evaluation in lignocellulosic hydrolysate for the production of single cell oils to be cost effective.