Estudo em diferentes concentrações de água residual de petróleo para o crescimento de Chlorella sorokiniana, Chlorella vulgaris, Desmodesmus spinosus e suas combinações

Abstract

Petroleum refining involves three steps: separation, conversion and reform. Within all these steps there is the use of water to obtain refined oil. The water that is used is discarded after refinement and when discarded in the environment without treatment, it introduces organic compounds that can be toxic to organisms. Microalgae are photosynthetic organisms and sensitive to various organic and inorganic compounds in the environment in which they are found. Studies on physiological changes serve to diagnose the fate of this wastewater and the impacts on aquatic ecosystems. The objective of this work was to analyze the impacts of wastewater from oil production on the physiology and biochemical composition of different species of microalgae. Three species of microalgae were cultivated in BG-11 medium: Chlorella sorokiniana, Chlorella vulgaris, Desmodesmus spinosus, in addition to their combinations: C. sorokiniana + D. spinosus; C. vulgaris + D. spinosus; C. sorokiniana + D. spinosus + C. vulgaris in different concentrations of wastewater and subsequently determined which concentration showed algae growth. After that, a residual water concentration (5%) was selected for the physiological and biochemical study of the different species of microalgae. The results showed that from 40% residual water there was inhibition of microalgal growth. In 5% of residual water, it was observed that D. spinosus had the growth rate and the photosynthesis affected. The cultures also showed higher dry weight, more carbohydrates than the control, higher chlorophyll a/b ratio. This work contributes to the understanding of the mechanisms by which these microalgae species deal with the conditions generated by wastewater.