Lipid and carotenoid synthesis by Rhodosporidium diobovatum, grown on glucose versus glycerol, and its biodiesel properties

Abstract

Relationships between lipid and carotenoid synthesis by Rhodosporidium diobovatum were investigated for cell cultures in nitrogen-limited medium (GMY) containing equimolar amounts of carbon of glucose or glycerol. The cultures were also supplemented with additional substrate at 120 h postinoculation (pi) and during a fed-batch experiment. Growth of R. diobovatum on glucose resulted in higher yields of triacyglycerides (TAGs) and carotenoid than when grown on glycerol, even though the cultures contained equimolar amounts of carbon. After the addition of fresh substrate at 120 h pi, total carotenoid concentrations were significantly different from the concentrations measured at 120 h pi in both glucose and glycerol cultures, with no concomitant increase in lipid concentrations, suggesting that carotenoid synthesis is linked to exponential-phase growth, while lipid synthesis is linked to stationary phase. We also compared the calculated properties of biodiesel that could be made with TAGs derived from R. diobovatum with properties of biodiesel made from TAGs of other oleaginous yeasts, microalgae, vegetable oils, and animal fats. This study shows that R. diobovatum can be an effective strain for production of neutral lipids containing high percentages of oleic acid, palmitic acid, and linoleic acid, as well as carotenoids.

Physiological and Phylogenetic Characterization of Rhodotorula diobovata DSBCA06, a Nitrophilous Yeast

“…babjevae , which form a distinct cluster with R. diobovata in the genus Rhodotorula ( Figure 1 ). Members of these species have been studied for nitrate assimilation [ 28 , 29 ] and extensively investigated as oleaginous yeasts for the production of carotenoids [ 18 , 30 ] and fatty acids [ 31 ].…”

“…Moreover, other metabolic features relevant for process optimization were evaluated, including carbon sources, pH optimum, and heavy metal tolerance. In the last decades, Rhodotorula species have found increasing applications in the production of biotechnologically interesting products, such as carotenoids, for pharmaceutical, chemical, food, and feed industries [ 14 , 15 ] as well as in bioremediation of oil-polluted environments and heavy metal biosorption [ 14 , 16 , 17 , 18 ]. Nevertheless, to our knowledge, this is the first report on the ability of a Rhodotorula yeast to efficiently assimilate nitrite and well tolerate concentrations up to 20 mM nitrite.…”

The Oleaginous Red YeastRhodotorula/Rhodosporidium: A Factory for Industrial Bioproducts

“…However, biofuel research has also focused on R. diobovatum as a second-generation biodiesel producer due to its ability to consume the impure glycerol waste that is created as a byproduct of first-generation biodiesel production [77]. For example, it was recently reported that R. diobovatum could be an "effective strain for production of neutral lipids" given its high yields of oleic, palmitic, and linoleic acid [79], although growth on glucose produced more TAGs than glycerol. Importantly, a glycerol consumption strategy would allow for the continued use and optimization of the first-generation biodiesel production pipelines, while simultaneously allowing investment in the development of second-generation approaches.…”

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

“…All mutated strains have a density of 0.85 g/cm 3 and a kinematic value varying from 3.69 to 4.35 ± 0.09 mm 2 /s that was confirmed to the value fixed in the international standard parameter of Biodiesel. The determination of the physical parameter of biodiesel (CV, IV, SN, HHV, viscosity, oxidation stability) of some genus of oleaginous yeast such as Rhodotorula [71–73], Rhodosporidium [14, 59, 74, 75], Cryptococcus [75], Debaryomyces [75], Yarrowia [75, 76], Trichosporon [44, 45] and Papiliaterma [77] predicted the good quality of biodiesel generated by those species. Comparing the results of biodiesel predicted to the different strains of this study, we found a similarity with the genus mentioned in some indices such as the cetane number, the iodine value, the kinematic value and cold filter plugging point which was close to the standard parameter of biodiesel (ASTM D6751, EN14214, Indian Biodiesel IS15607 and the commercial biodiesel).…”

“…The accumulation of fat in yeast is affected by several parameters that may be grouped as physical (e.g., pH, temperature, light) and chemical (e.g., carbon and nitrogen sources) [10, 11]. However, the TAGs synthesized by oleaginous yeasts consist primarily of C16 and C18, such as C16:0, C16:1, C18:0 C18:1 and 18:2 [12, 13], with varying amounts of shorter (C14) and longer (C26) fatty acid chains, which have key roles in protein modification [14]. The fatty acid (FA) composition of the microbial lipids was found to be similar to vegetable oil, which is commonly used in biodiesel production.…”