Produção de biocompostos por Rhodotorula mucilaginosa utilizando o hidrolisado do sisal (Agave sisalana) como substrato

Abstract

The search for alternative sources of biocomposites with potential for application in several sectors with the ability to accumulate carotenoids and lipids inside their cells, have been extensively studied. The aim of this study was to evaluate the potential of sisal fiber and sisal pulp hydrolysates as substrates for the production of lipids and carotenoids by the yeast Rhodotorula mucilaginosa. The yeast cells were inoculated into the fiber hydrolyzate and sisal pulp, the cultures were incubated in an orbital shaker at 30 °C and 200 rpm. During the 120 h interval, biomass and reducing sugars were quantified. In order to determine the variables that most influence the cultivation of the yeast Rhodotorula mucilaginosa, using sisal bagasse hydrolyzate as a substrate, a Plackett-Burman planning was carried out with 8 input variables: KH2PO4 (g/L), MgSO4 (g/L), temperature (°C), initial pH, yeast extract (g/L), CaCl2 (g/L), (NH4) SO4 (g/L) and NaCl (g/L) and 3 response variables : biomass (g/L), specific production of carotenoids (μg/g) and volumetric production of carotenoids (g/L), totaling 15 assays. Were produced 4.98 g/L of biomass, 19.28 g/100 g of lipids and 0.48 mg/L of carotenoids, using the sisal fiber hydrolyzate as a substrate. The yeast carotenoid production was mainly influenced by temperature and pH, with maximum biomass obtained at 34.0 ºC and pH 5.0, and maximum carotenoid synthesis at 22.0 ºC and pH of 7.0. The yeast grew and accumulated carotenoids and lipids using fiber and sisal pulp hydrolyzate as substrates, producing as maximum values 4.98 g/L of biomass, 19.28% of lipids and 0.49 mg/L of carotenoids, using fiber and 12.87 g/L of biomass, 0.54 g of lipids/L of substrate and 1.13 g/L of carotenoids, using sisal pulp. In the fatty acid profile of the oil obtained, there was a predominance of unsaturated, mainly oleic and linoleic. The hydrolyzates of fiber and sisal pulp proved to be an adequate means for the production of lipids and carotenoids by the yeast Rhodotorula mucilaginosa. The lignocellulosic materials studied have potential to generate hydrolyzates that can be used as a substrate for the cultivation of Rhodotorula mucilaginosa yeast, aiming at obtaining biocomposites, allowing added value to the residue (sisal pulp) and fiber, in addition to minimizing the environmental impacts caused due to improper disposal, with potential for application in the food, chemical, pharmaceutical and cosmetics sectors.