Comparison of oleate conversion under microaerophilic and anaerobic conditions

Excessive accumulation of Long Chain Fatty Acids (LCFA) in methanogenic bioreactors is the cause of process failure associated to a severe decrease in methane production. In particular, fast and persistent accumulation of palmitate is critical and still not elucidated. Aerobes or facultative anaerobes were detected in those reactors, raising new questions on LCFA biodegradation. To get insight into the influence of oxygen, two bioreactors were operated under microaerophilic and anaerobic conditions, with oleate at 1 and 4 gCOD/(L d). Palmitate accumulated up to 2 and 16 gCOD/L in the anaerobic and microaerophilic reactor, respectively, which shows the importance of oxygen in this conversion. A second experiment was designed to understand the dynamics of oleate to palmitate conversion. A CSTR and a PFR were assembled in series and fed with oleate under microaerophilic conditions. HRT from 6 to 24 h were applied in the CSTR, and 14 to 52 min in the PFR. In the PFR a biofilm was formed where palmitate accounted for 82% of total LCFA. Pseudomonas was the predominant genus (42 %) in this biofilm, highlighting the role of aerobic and facultative anaerobic bacteria in LCFA bioconversion.

Cruzar o mar na formação e na ação : narrativas de professores portugueses e brasileiros

A mobilidade de pessoas entre países é muito comum nos dias de hoje, e ao movimentarem-se as pessoas levam consigo saberes, experiências e propósitos. Assim acontece com alguns professores que fazem a sua formação no Brasil e mais tarde exercem a docência em Portugal; assim acontece também com professores que se formam em Portugal e desenvolvem a sua ação docente no Brasil. É neste caminho de ida e volta que, no contato direto com professoras que fizeram estas viagens, procuramos analisar como as mesmas mobilizam para as suas narrativas os seus saberes e experiências para se desenvolverem como profissionais e darem as melhores respostas aos seus alunos, em países que as acolhem após esse período formativo. Como se situam na ação docente? Como fazem a sua inserção socioideológica e política? O que ganham e o que perdem nestas transações? Que significados se atribuem enquanto professoras? A base empírica da pesquisa baseia-se na análise de narrativas, uma de uma professora que realizou a sua formação pedagógica e desenvolveu alguma atividade profissional no Brasil e que atualmente atua no sistema educativo português, e outra de uma professora brasileira, com formação de base feita no seu país, tendo posteriormente prolongado a sua formação em Portugal, estando atualmente a lecionar no seu país de origem. As conclusões preliminares apontam para um amplo conjunto de indicadores da identidade de ser professor, como, por exemplo, a interação ser a base de toda a ação educativa, a riqueza que o cruzamento de saberes e experiências proporciona, a necessidade de cada um conseguir fazer o cruzamento entre vivências pessoais e profissionais e a pertinência da contextualização educativa.

Nutritional value, bioactive compounds and antioxidant properties of three edible mushrooms from Poland

Mushrooms contain a multitude of biomolecules with nutritional and/or biological activity. Among the bioactive molecules, phenolic compounds and tocopherols are the most responsible for their antioxidant activity. In the present work, Boletus edulis, Lentinus edodes and Xerocomus badius, three edible mushroom species originated from Poland, were analyzed for their chemical composition and antioxidant activity. Carbohydrates were the most abundant macronutrients, followed by proteins and ash. Fructose, mannitol and trehalose were the prevalent sugars, but glucose was only found in B. edulis. Polyunsaturated fatty acids predominated over mono and saturated fatty acids. Palmitic, oleic and linoleic acids were abundant in the three samples. α- and β- Tocopherols were quantified in all the samples, but γ-tocopherol was only identified in X. badius. Oxalic and fumaric acids were quantified in the three samples; quinic acid was only present in L. edodes, and malic and citric acids were only found in X. badius. p-Hydroxybenzoic, protocatechuic and cinnamic acids were quantified in all the species, while p-coumaric acid was only found in B. edulis. This species and X. badius revealed the highest antioxidant properties, being B. edulis more effective in radicals scavenging activity and reducing power, and X. badius in lipid peroxidation inhibition, which is related with the highest amounts in phenolic compounds and tocopherols, respectively.