Yeasts and bacterial biosurfactants as demulsifiers for petroleum derivative in seawater emulsions

Abstract Oil sludge or waste generated in transport, storage or refining forms highly stable mixtures due to the presence and additives with surfactant properties and water forming complex emulsions. Thus, demulsification is necessary to separate this residual oil from the aqueous phase for oil processing and water treatment/disposal. Most used chemical demulsifiers, although effective, are environmental contaminants and do not meet the desired levels of biodegradation. We investigated the application of microbial biosurfactants as potential natural demulsifiers of petroleum derivatives in water emulsions. Biosurfactants crude extracts, produced by yeasts (Candida guilliermondii, Candida lipolytica and Candida sphaerica) and bacteria (Pseudomonas aeruginosa, Pseudomonas cepacia and Bacillus sp.) grown in industrial residues, were tested for demulsification capacity in their crude and pure forms. The best results obtained were for bacterial biosurfactants, which were able to recover about 65% of the seawater emulsified with motor oil compared to 35–40% only for yeasts products. Biosurfactants were also tested with oil-in-water (O/W) and water-in-oil (W/O) kerosene model emulsions. No relationship between interfacial tension, cell hydrophobicity and demulsification ratios was observed with all the biosurfactants tested. Microscopic illustrations of the emulsions in the presence of the biosurfactants showed the aspects of the emulsion and demulsification process. The results obtained demonstrate the potential of these agents as demulsifiers in marine environments

Influência da dor crônica na capacidade funcional de idosos institucionalizados

Este estudo teve por objetivo analisar a influência da dor quanto à duração, localização e intensidade na capacidade funcional de idosos institucionalizados. Trata-se de um estudo tansversal a partir de uma amostra de 60 idosos. O instrumento foi composto por variáveis sociodemográficas, de saúde, escala numérica de dor e Índice de Barthel. Com a aplicação do Teste Qui-quadrado verificou-se diferença estatística significante entre presença de dor e as atividades: banho (p=0,015) vestir-se (p=0,041), transferência para higiene intima (p=0,001), transferência cama e cadeira (p=0,032), deambulação (p=0,010) e subir escadas (p=0,008) e a pontuação do Índice de Barthel e presença de dor, p<0,000. Diante dos resultados deste estudo constatou-se que a dor interfere de maneira negativa na capacidade funcional dos idosos