Aprovechamiento de vinaza para producción de lípidos y biomasa microbiana mediante cultivo mixto de Yarrowia lipolytica (Wickerham, Kurtzman & Herman) van der Walt & von Arx y Chlorella vulgaris Beijerinck

Abstract

Recent studies have shown the benefits of mixed cultures between microalgae and yeasts to obtain compounds of industrial interest, such as biodiesel. In order to evaluate the production of biomass and lipids, the growth of Yarrowia lipolytica and Chlorella vulgaris using sugarcane vinasse as substrate was studied. Three different proportions of vinasse in distilled water (75, 50, and 25% in volume) were evaluated, and four initial inoculum proportions of Y. lipolytica and C. vulgaris (100%, 98%, 95% y 0% of Y. lipolytica of total cells inoculum). They were cultured in aerated reactors at a constant flow rate of 3 L.min^-1, pH 6.7, 25 °C for 240 hours, cell growth curves were made by direct cell counting under a microscope, and biomass curves by dry weight. Lipids were extracted from the dry biomass according to Bligh and Dyer’s method. Dry biomass productivity and lipid percentage were determined. The best conditions were a pure culture of Y. lipolytica with 50% vinasse that reached 20.92±12.39% of lipids, and a biomass productivity of 54.58±4.49 mg.L^-1.d^-1; and a mixed culture with an initial inoculum of 98% Y. lipolytica and 25% vinasse, with biomass productivity of 102.67±32.07 mg.L^-1.d^-1 and a lipid percentage of 7.06 ± 1.76%. Although the favorable effect of a mixed culture among these species was observed under some conditions, the monoculture of Y. lipolytica provided better results in the evaluated conditions. It was possible to cultivate oleaginous strains in an effluent diluted in water without adding an organic carbon source.