Percorrer por autor "Belo, Isabel"
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- Characterization of phenolic compounds of OMW: toxicity and degrability by yeastsPublication . Gonçalves, Cristiana; Ferreira, João P.; Lopes, Marlene; Falcão, Soraia; Peres, António M.; Cardoso, Susana M.; Belo, IsabelThe olive oil extraction, performed by the 3-phases process, results on a large amount of an effluent, usually known as Olive Mill Wastewater (OMW). It is mainly produced in the Mediterranean area, with the exception of Spain that is one of the major producers but mostly use the 2-phases process. OMW represents a major environmental problem due to its high organic content, being characterized by a strong acidic smell and an intensive brown to dark color due to the presence of biodegradable, recalcitrant and biostatic compounds. OMW phytotoxicity can be attributed to the phenolic compounds (Lanciotti et al, 2005). Owing to their instability, OMW phenols tend to polymerise during storage into condensed high-molecular-weight polymers that are difficult to degrade (Crognale et al, 2006). Thus, uncontrolled OMW disposal can create severe risks to water and soil quality. OMW is currently concentrated by evaporation in open pools, but this method is not satisfactory because a black foul-smelling sludge, difficult to remove, is produced. Instead of disposal solutions an approach of using this waste as a resource to be valorized is of greater interest. In fact, OMW contains sugars, lipids, mineral elements and phenolic compounds (10 % of the organic matter) that could be either directly recovered by chemical extraction and subsequent purification, or utilized as a basis for fermentative processes.
- Characterization of phenolic compounds of OMW: toxicity and degradability by yeastsPublication . Gonçalves, Cristiana; Ferreira, João P.; Lopes, Marlene; Falcão, Soraia; Peres, António M.; Cardoso, Susana M.; Belo, IsabelThe characterization of Olive Mill Wastewaters (OMW), focusing the phenolic compounds, is one of the aims of the present work. As a first approach to characterize the phenolic compounds of OMW, the extraction methods used were: a liquid-liquid extraction by acidified ethyl acetate and a solid-liquid extraction with acidified methanol. The analysis of these extracts by reversed phase liquid chromatography confirmed that hydroxytyrosol was the most abundant phenolic compound in OMW, and that this compound was more efficiently recovered by the solid-liquid extraction technique. It was also a goal of this work to study the phenolic compounds toxicity to some yeast strains. Among the phenolic compounds tested catechol is the most inhibitory one to the cells. The phenols degradation was quite difficult, particularly when more easily degradable carbon source is still present in the medium.