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Author(s): Joana A. Loureiro
Carla Ferreira
Ana L. Gonçalves
José C. M. Pires
Manuel Simões
Title: Surface physicochemical properties of selected single and mixed cultures of microalgae and cyanobacteria and their relationship with sedimentation kinetics
Issue Date: 2015
Abstract: Background: Microalgae are photosynthetic microorganisms presenting a diversity of biotechnological applications.However, microalgal cultivation systems are not energetically and economically feasible. Possible strategies that canbe applied to improve the feasibility of microalgal production include biofouling control in photobioreactors, theuse of attached growth systems and bioflocculation. These processes are ruled by surface physicochemical properties.Accordingly, the surface physicochemical properties of Chlorella vulgaris, Pseudokirchneriella subcapitata, Synechocystissalina and Microcystis aeruginosa were determined through contact angle and zeta potential measurements.Additionally, mixed cultures of the selected microorganisms were performed. Sedimentation kinetics of the studiedcultures was also evaluated to understand how surface physicochemical properties influence microalgal recovery.Results: All studied microorganisms, except S. salina, presented a hydrophilic surface. The co-culture of S. salina with theother studied microorganisms resulted in a more hydrophobic algal suspension. Regarding zeta potential determinations,all studied suspensions presented a negatively charged surface (approximately -40.8 ± 4.4 mV). Sedimentation experimentshave shown that all microalgal suspensions presented low microalgal recovery efficiencies. However, a negative linearrelationship between microalgal removal percentage and free energy of hydrophobic interaction was obtained.Conclusions: The evidence of a relationship between microalgal removal percentage and free energy of hydrophobicinteraction demonstrates the importance of surface physicochemical properties on microalgal settling. However, the lowrecovery efficiencies achieved, as well as the high net zeta potential values determined, indicate that another factor to considerin microalgal settling is the ionic strength of the culture medium, which play an important role in suspensions' stability.
Subject: Engenharia de bioprocessos, Engenharia de projecto, Engenharia do ambiente
Bioprocess engineering, Project engineering, Environmental engineering
Scientific areas: Ciências da engenharia e tecnologias::Engenharia do ambiente
Engineering and technology::Environmental engineering
Related Information: info:eu-repo/grantAgreement/Autoridade de Gestão do Programa Operacional de Cooperação Transfronteiriça Espanha-Portugal/Programa Operacional de Cooperação Transfronteiriça Espanha-/0687_NOVOMAR_1_P/Consolidação do Centro Multipolar de Valorização de Recursos Marinhos visando novos usos do mar/NOVOMAR
info:eu-repo/grantAgreement/Autoriadade de Gestão do Programa Operacional Regional do Norte/Programas Integrados de IC&DT/NORTE-07-0124-FEDER-000025/(Bio) Chemical Engineering: Multi-Scale Approaches for Sustainable Environment and Health/LEPAE/CEFT - RL2
info:eu-repo/grantAgreement/FCT - Fundação para a Ciência e Tecnologia/Projetos Estratégicos/PEst-C/EQB/UI0511/2013/PROJECTO ESTRATÉGICO - UI 511 - 2013-2014/UI0511
Document Type: Artigo em Revista Científica Internacional
Rights: restrictedAccess
Appears in Collections:FEUP - Artigo em Revista Científica Internacional

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