Investigations of biofilms formed on silica in contact with aqueous formulations containing laccase and maltodextrin

• Autor(a) principal: Corrales Ureña, Yendry Regina [UNESP]
• Data de Publicação: 2016
• Outros Autores: Gaetjen, Linda, Nascimento, Matheus Vieira, Filho, Paulo Noronha Lisboa [UNESP], Cavalcanti, Welchy Leite, Noeske, Paul-Ludwig Michael, Rischka, Klaus
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.1186/s40563-016-0059-3; http://hdl.handle.net/11449/169550
• topic: Adhesion of biofilms; Biopolymer adsorption; Laccase maltodextrin mixture; Surface analysis and monitoring

The formation of nano-scale biofilms on hydrophilic silica surfaces from aqueous polypeptide/polysaccharide mixtures containing laccase and maltodextrin was investigated in situ with quartz crystal microbalance with dissipation monitoring (QCM-D). Surface analysis techniques such as X-ray photoelectron spectroscopy (XPS), optically stimulated electron emission (OSEE) and atomic force microscopy (AFM) were applied for characterizing the resulting layers obtained after periods varying from a few seconds to several hours of contact between the substrate and the biopolymers formulation. The biofilm formation in contact with the aqueous laccase/maltodextrin suspension was studied at pH level 4.75, under conditions close to the isoelectric point of the enzyme. The few nanometers rough biofilms obtained were composed of a laccase/maltodextrin mixture, and their thickness was observed to steadily increase during 4 h of contact with the aqueous mixture of biopolymers. Remarkably, the still adhesive films obtained after 1 h of contact with aqueous polypeptide/polysaccharide mixture resisted a 30 min rinsing with acetate buffer. The biofilms growing process was monitored using OSEE, due to the effected attenuation of the UV-induced electron emission from the SiO2/Si substrate, which was found to be more pronounced than the attenuation of the photoelectrons from the substrate which contribute to the XPS signals. Layers as thin as 1 nm were detected by the OSEE.