Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/243757
Type: Artigo de periódico
Title: Breaking Oil-in-water Emulsions Stabilized By Yeast
Author: Furtado
Guilherme F.; Picone
Carolina S. F.; Cuellar
Maria C.; Cunha
Rosiane L.
Abstract: Several biotechnological processes can show an undesirable formation of emulsions making difficult phase separation and product recovery. The breakup of oil-in-water emulsions stabilized by yeast was studied using different physical and chemical methods. These emulsions were composed by deionized water, hexadecane and commercial yeast (Saccharomyces cerevisiae). The stability of the emulsions was evaluated varying the yeast concentration from 7.47 to 22.11% (w/w) and the phases obtained after gravity separation were evaluated on chemical composition, droplet size distribution, rheological behavior and optical microscopy. The cream phase showed kinetic stability attributed to mechanisms as electrostatic repulsion between the droplets, a possible Pickering-type stabilization and the viscoelastic properties of the concentrated emulsion. Oil recovery from cream phase was performed using gravity separation, centrifugation, heating and addition of demulsifier agents (alcohols and magnetic nanoparticles). Long centrifugation time and high centrifugal forces (2 h/150,000 x g) were necessary to obtain a complete oil recovery. The heat treatment (60 degrees C) was not enough to promote a satisfactory oil separation. Addition of alcohols followed by centrifugation enhanced oil recovery: butanol addition allowed almost complete phase separation of the emulsion while ethanol addition resulted in 84% of oil recovery. Implementation of this method, however, would require additional steps for solvent separation. Addition of charged magnetic nanoparticles was effective by interacting electrostatically with the interface, resulting in emulsion destabilization under a magnetic field. This method reached almost 96% of oil recovery and it was potentially advantageous since no additional steps might be necessary for further purifying the recovered oil. (C) 2015 Elsevier B.V. All rights reserved.
Subject: Saccharomyces-cerevisiae
Biodiesel Production
Solid Particles
Recent Trends
Surface
Cells
Demulsification
Emulsification
Bioemulsifier
Challenges
Country: AMSTERDAM
Editor: ELSEVIER SCIENCE BV
Rights: embargo
Identifier DOI: 10.1016/j.colsurfb.2015.03.010
Address: http://www.sciencedirect.com/science/article/pii/S0927776515001447
Date Issue: 2015
Appears in Collections:Unicamp - Artigos e Outros Documentos

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