Obtención de lípidos a partir de biomasa cultivada en agua residual de origen porcino

Abstract

Microalgae are photosynthetic microorganisms with high lipid content, capable of degrading nutrients from wastewater. In this research, microalgal biomass from Scenedesmus sp. and Chlorella vulgaris in wastewater from pig slaughter previously sterilized was cultivated in flat photobioreactors exposed to the atmospheric conditions in Quito. Cell growth and physicochemical parameters of the cultivation were measured, previous biomass culturing and lipid extraction. Total lipids were characterized in form of free fatty acids (FFA) and fatty acid methyl esters (FAMEs) to determine their possible use in the production of biofuels. The results indicated a higher biomass growth for Scenedesmus sp. compared to Chlorella vulgaris (0.41 g / L vs 0.2 g / L), it was also shown that these species can be used in bioremediation processes due to the percentages of nutrient removal achieved (70.67% of TN, 60.91% of TP and 67.12% of TC for Scenedesmus sp. and 87.89% TN, 61.92% of TP and 77.08% of TC for Chlorella vulgaris). Of the six lipid extracting solvents tested, only methylcyclohexane, chloroform: methanol (1: 2), and ethyl acetate had better yields of lipids and FFA. The percentages of FAMEs from FFA were in the range of 52.5% to 89.5% for Scenedesmus sp., and for Chlorella vulgaris from 51% to 80.5% by weight. Although the values of lipids, FFA and FAMEs are below of the range reported by other authors, the use of this type of wastewater as culture medium for the two microalgae species, cannot be ruled out for lipid extraction in biofuel production.