COLD-ADAPTED OLEAGINOUS YEASTS: EFFECT OF GLUCOSE CONCENTRATION ON LIPIDS PRODUCTION OF Rhodotorula glutinis

ANGELICOLA M.V.; VIÑARTA S.C.; AYBAR M.J.; FIGUEROA L.I.C.

CABA, Buenos Aires

Congreso; Reunión Conjunta de Sociedades de Biociencias y SAIB 2017; 2017

Sociedades de Biociencias (SAIB, SAIC, SAI, SAI, SAA, SAB, SAFE,SAFIS, SAH, SAP)

Certain oleaginous yeasts as Rhodotorula glutinis can accumulate neutral storage lipids from 20 to 70% of biomass, consisting in triacylglycerols (TAG), under appropriate cultivation conditions. Microbial TAGs represent a valuable alternative feedstock for biodiesel production. Lipid accumulation in oleaginous microorganism occurs under nutrient limitations, mainly nitrogen, with a simultaneous excess of carbon source. Effect of glucose concentration and C/N ratio on the growth and lipid production of two of Rhodotorula glutinis (R4 and R48) isolated from Antarctica was investigated. Yeasts were cultured aerobically for 120 h in nitrogen-limited medium (MI), with different glucose concentrations (30, 40 and 100 g/L). Growth was determinedby DO (ë = 600 nm) every 24 h. Samples were taken at 72, 96 y 120 h of culture for analytical determinations (pH, biomass, lipid production, percentage of lipid accumulation and residual glucose). Results showed an increase of the parameters as a function of the culture time for the three glucose concentrations evaluated, in both strains. Comparatively, the biomass achieved by R. glutinis R48 (12.33, 13.83 and 13 g/L) was superior to R. glutinis R4 (10.35, 10.83 and 8.42 g/L) at 30, 40 and 100 g/L of initial glucose. Statistically, the lipid production of R. glutinis R4 (~3.13-5.89 g/L) and R. glutinis R48 (~6.16-7.35 g/L) was not significantly different after 72 and 96 h of culture, respectively. There were no significant differences in the lipid accumulation of R. glutinis R48 (~49.94-57.71%) in the evaluated concentrations nor during the culture time. However R. glutinis R4 reached the highest lipid accumulation (50.25%) in the medium with 100 g/L of glucose. The production and lipid accumulation of these strains are among the highest reported in the literature for oleaginous yeasts. Based on these results we conclude that R. glutinis R4 and R. glutinis R48 have an interesting capacity for lipid production and exhibit promising perspectives to design processes of production of TAG with potential application for the generation of biodiesel.