title: Biodegradation improvement of poly(3-hydroxy-butyrate) films by entomopathogenic fungi and UV-assisted surface functionalization.
abstract: Ultraviolet (UV)-assisted surface modification in the presence of oxygen was used as initial step to achieve controlled degradation of poly(3-hydroxy-butyrate), PHB, films by entomopathogenic fungi. Treated surfaces were investigated by surface analysis techniques (water contact angle, Fourier Transformed Infrared Spectroscopy in Attenuated Total Reflectance mode, X-ray Photoelectron Spectroscopy, Near-edge X-ray Absorption Fine Structure, Gel Permeation Chromatography, Optical Microscopy, Scanning Electron Microscopy, and weight loss). After the UV-assisted treatments, new carbonyl groups in new chemical environments were detected by XPS and NEXAFS spectroscopy. The oxidizing atmosphere did not allow the formation of CC bonds, indicating that Norrish Type II mechanism is suppressed during or by the treatments. The higher hydrophilicity and concentration of oxygenated functional groups at the surface of the treated films possibly improved the biodegradation of the films. It was observed a clear increase in the growth of this fungus when oxygenated groups were grafted on the polymers surfaces. This simple methodology can be used to improve and control the degradation rate of PHB films in applications that require a controllable degradation rate.
authors.affiliation: Laboratório de Fotoquímica e Superfícies, Departamento de Físico-Química, Instituto de Química, UFRGS, Av. Bento Gonçalves, 9500, CEP 91501-970, Porto Alegre, RS, Brazil. Electronic address: felipekessler@gmail.com.
authors.forename: Felipe
authors.initials: F
authors.lastname: Kessler
authors.affiliation: Laboratório de Fungos de Importância Médica e Biotecnológica, Departamento de Biologia Celular e Molecular, Centro de Biotecnologia, UFRGS, Av. Bento Gonçalves, 9500, CEP 91501-970, Porto Alegre, RS, Brazil.
authors.forename: Leticia
authors.initials: L
authors.lastname: Marconatto
authors.affiliation: Laboratório de Fungos de Importância Médica e Biotecnológica, Departamento de Biologia Celular e Molecular, Centro de Biotecnologia, UFRGS, Av. Bento Gonçalves, 9500, CEP 91501-970, Porto Alegre, RS, Brazil.
authors.forename: Roberta da Silva Bussamara
authors.initials: Rda S
authors.lastname: Rodrigues
authors.affiliation: Laboratório de Fotoquímica e Superfícies, Departamento de Físico-Química, Instituto de Química, UFRGS, Av. Bento Gonçalves, 9500, CEP 91501-970, Porto Alegre, RS, Brazil.
authors.forename: Gabriela Albara
authors.initials: GA
authors.lastname: Lando
authors.affiliation: Laboratório de Fungos de Importância Médica e Biotecnológica, Departamento de Biologia Celular e Molecular, Centro de Biotecnologia, UFRGS, Av. Bento Gonçalves, 9500, CEP 91501-970, Porto Alegre, RS, Brazil.
authors.forename: Augusto
authors.initials: A
authors.lastname: Schrank
authors.affiliation: Laboratório de Fungos de Importância Médica e Biotecnológica, Departamento de Biologia Celular e Molecular, Centro de Biotecnologia, UFRGS, Av. Bento Gonçalves, 9500, CEP 91501-970, Porto Alegre, RS, Brazil.
authors.forename: Marilene Henning
authors.initials: MH
authors.lastname: Vainstein
authors.affiliation: Laboratório de Fotoquímica e Superfícies, Departamento de Físico-Química, Instituto de Química, UFRGS, Av. Bento Gonçalves, 9500, CEP 91501-970, Porto Alegre, RS, Brazil. Electronic address: danielw@iq.ufrgs.br.
authors.forename: Daniel Eduardo
authors.initials: DE
authors.lastname: Weibel
mesh_terms: D006885:Hydroxybutyrates / Q000737:chemistry / Q000378:metabolism* / Q000528:radiation effects*; D006999:Hypocreales / Q000378:metabolism*; D010100:Oxygen / Q000737:chemistry; D011091:Polyesters / Q000737:chemistry / Q000378:metabolism* / Q000528:radiation effects*; D013499:Surface Properties; D014466:Ultraviolet Rays; D000094122:Polyhydroxybutyrates
chemical_list: D006885:Hydroxybutyrates; D010100:Oxygen; D011091:Polyesters; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates
keywords: Controlled degradation; Entomopathogenic fungi; Metarhizium anisopliae; Poly(3-hydroxy-butyrate); Surface modification; UV-assisted