Lipids of Rhodotorula mucilaginosa IIPL32 with biodiesel potential: Oil yield, fatty acid profile, fuel properties

Abstract

This study analyzes the single cell oil (SCO), fatty acid profile, and biodiesel fuel properties of the yeast Rhodotorula mucilaginosa IIPL32 grown on the pentose fraction of acid pre-treated sugarcane bagasse as a carbon source. The yeast biomass from nitrogen limiting culture conditions (15.3 g L ) was able to give the SCO yield of 0.17 g g of xylose consumed. Acid digestion, cryo-pulverization, direct in situ transesterification, and microwave assisted techniques were evaluated in comparison to the Soxhlet extraction for the total intracellular yeast lipid recovery. The significant differences were observed among the SCO yield of different methods and the in situ transesterification stood out most for effective yeast lipid recovery generating 97.23 mg lipid as FAME per gram dry biomass. The method was fast and consumed lesser solvent with greater FAME yield while accessing most cellular fatty acids present. The yeast lipids showed the major presence of monounsaturated fatty esters (35-55%; 18:1, 16:1) suitable for better ignition quality, oxidative stability, and cold-flow properties of the biodiesel. Analyzed fuel properties (density, kinematic viscosity, cetane number) of the yeast oil were in good agreement with international biodiesel standards. The sugarcane bagasse-derived xylose and the consolidated comparative assessment of lab scale SCO recovery methods highlight the necessity for careful substrate choice and validation of analytical method in yeast oil research. The use of less toxic co-solvents together with solvent recovery and recycling would help improve process economics for sustainable production of biodiesel from the hemicellulosic fraction of cheap renewable sources.

Species disparity response to mutagenesis of marine yeasts for the potential production of biodiesel

“…Li et al [57] confirmed that R. muciloginosa TJY15a constitute a good feedback for biodiesel production. Arora et al [59] and Khot and Ghosh [65] reported, respectively, the same conclusion for C. minutissima cultivated in optimal condition of lipid productivity (N L P L ) and for the oleaginous yeast R. mucilaginosa IIPL32.…”

“…[30]; Chlorella minutissima [60]; Mortierella isabellina [61], Y. lipolytica in POME [62], R. mucilaginosa [63] and L. starkeyi [64]. Khot and Ghosh [65] found a similar result for the strain R. mucilaginosa IIPL32. Brar et al report that the fatty acid profile of wild Trichosporon sp.…”

“…According to Knothe [78], the quality of biodiesel depends on the fatty acid composition of the biolipids. Conferring to Khot and Ghosh [65], high monounsaturated fat content is a good quality of biodegradable product. Dai et al [4] reported that R. glutinis could be a potential strain for biodiesel production according to his lipid profile.…”

“…According to international standards, biodiesel must follow some criteria such as ASTM 6751-3 (USA), EN 14214 (Europe) and Bureau of Indian Standard (IS 15607-05) for biodiesel [27]. The fatty acid profile determines the quality of biodiesel and it has been recommended that higher proportions of methyl esters of both C16 and C18 SFAs and MUFAs with reasonable amounts of PUFAs are required for a good quality of Biodiesel [1, 65, 69]. Table 6 shows the characteristics of the biodiesel from the wild RmTun15, YlTun15 and TaTun15 and their mutant strain MR-2, MR-3, MY-2, MY-3, MT-2, MT-3.…”

Assessment of fuel properties on the basis of fatty acid profiles of oleaginous yeast for potential biodiesel production

“…Sugarcane bagasse, sugar cane husk, wheat straw, rice straw and corn stover are the most promising non-edible lignocellulose biomasses/feedstocks in U.S.A, Asia, and Europe [70][71][72]. Recently, Rhodotorula mucilaginosa IIPL32 grown on the pentose fraction of acid pretreated sugarcane bagasse as a carbon source synthesized 15.3 g/l biomass along with 0.17 g single cell oil as per g of xylose consumed [73]. Certain oleaginous yeast such as Cystobasidium oligophagum JRC1 is capable of cellulase and lipase production simultaneously when grown on a wide range of substrates including carboxymethylcellulose (CMC) and accumulated 36.46% (w/w) lipid on the medium with CMC as sole carbon source [74].…”