INVESTIGADORES
AYBAR Manuel Javier
congresos y reuniones científicas
Título:
Effect of glucose concentration on growth and fatty acids profile of two Rhodotorula glutinis strains
Autor/es:
M. VIRGINIA ANGELICOLA; MANUEL J. AYBAR; LUCIA I. CASTELLANOS FIGUEROA; SILVANA C. VIÑARTA
Lugar:
CABA
Reunión:
Congreso; XVII Jornadas de la Sociedad Uruguaya de Biociencias (SUB) y XX Jornadas Anuales de la Sociedad Argentina de Biología (SAB); 2018
Institución organizadora:
Sociedad Argentina de Biologia y Sociedad Uruguaya de Biociencias
Resumen:
Certain oleaginous yeasts as Rhodotorula glutinis can accumulate neutral lipids up to 70% of drybiomass, consisting mainly in triacylglycerols (TAG), under appropriate cultureconditions. Microbial TAG represent a valuable alternative feedstock forbiodiesel production. Lipid accumulation occurs under nutrient limitations,mainly nitrogen, with simultaneous excess of carbon source. The lipid synthesisand fatty acids (FA) composition are influenced by several factors as carbonsource (type and concentration), aeration, growth, temperature, C/N ratio, pH,among others parameters.. Effect of initial glucose concentration (30, 40 and 100 g L-1) on growth,lipid synthesis and FA profile of two strains of R. glutinis (R4 and R48) isolated from Antarctica was investigatedusing a nitrogen-limited medium (MI). Yeasts were incubated aerobically on arotatory shaker during 120 h at 250 rpm and 25 °C. Analyticaldeterminations (biomass, lipid production, lipid content and residual glucose) wereperformed after 120 h of culture time. Glucose affected the growth of thestrains and the FA profile of the microbial TAG. According to the results, thegrowth exhibited by R48 (12.33-13.83 g L-1) were higher than R4 (8.42-10.83g L-1) for all glucose concentrations assayed. An increase of thelipid content (from 50.6 to 60.2%) and a decrease of the biomass were exhibitedby R4 when the glucose concentration increased from 30 to 100 g L-1.However, significant differences on lipid accumulation and growth were notobserved for R48. The FA profile of microbial lipids was analyzed by GC-FID(Viñarta et al. 2016). FA with chain length between 14 and 18 carbons dominatedthe lipidic profile of both strains. Eighteen-carbons FA were the most abundant(68.27-85.59%). The increase of glucose concentration affected the FAcomposition of the yeasts. Higher glucose concentrations caused an increase inthe relative abundance of oleic and palmitic acids with a simultaneous decreaseof linoleic and linolenic acids in in the FA content of R48 strain. Differenteffect of glucose concentration was observed in R4 and a decrease of oleic andlinoleic acids with an increase of palmitic acid were observed at the highestglucose concentration. Results demonstrate that the FA profile of R. glutinis R4 and R. glutinis R48 are comparable with other oleaginous yeasts reportedin the literature. The better FA composition as feedstock for biodiesel wasobserved by R4 with 30 g L-1 of glucose, whilst for R48, with 100 g L-1.The FA profile of R. glutinis R4,with a high content of oleic acid (~60%), is quite similar to vegetables oils,indicating that its lipids have potential as a feedstock for biodieselproduction.