Publicação

Bioremediation and biodegradation of selected polyaromatic hydrocarbons by fungi

Ver documento

Detalhes bibliográficos
Resumo:Despite the amount of pollutants in the ecosphere has been increasing for a long time, soil contaminated with polyaromatic hydrocarbons (PAH) still remains one of the most important environmental problems worldwide. PAH are universal pollutants with a big variation in their concentration levels in different regions. PAH tend to bind to clays as these have high surface area, which allows more binding and adsorption of PAH on finer soil fractions. However, clay particles reduce in size as time goes by, diminishing porosity and transferable species in soil, and with aging of PAH also lose bioavailability, becoming persistent. Despite the different reported bioremediation techniques, this work focus on the biological degradation of PAH with fungi and their enzymes, mainly laccase and laccase-mediator systems. Laccases are receiving attention from different researchers due to their specific nature. They may be used in different industrial applications as they present the ability to oxidize a broad spectrum of phenolic and nonphenolic compounds. Moreover, processes with laccases are quite competitive with conventional chemical processes in different industries. However, the main limiting factor to their application still remains – large-scale production of laccase, mainly of highly active and stable laccase, is still to be attained. The work is globally divided into two parts, depending on the soil used: artificially contaminated or naturally contaminated soils. In the first part of this work the effect of soil pH and of different supports was evaluated, and the enzyme activities during the PAH degradation in soil were measured. Moreover, laccase degradation was set up, produced by fungal co- cultivation, using kiwi peels as substrate. The produced laccase was applied to PAH contaminated soil to evaluate its efficiency on enzymatic bioremediation. In a second part, heavily PAH and metals polluted soil obtained from Lagos, Nigeria, was used. Trametes versicolor was isolated from this soil and used in degradation experiments, with plantain peels as support. Laccase degradation assays were also set up, in batch and in PBR, with and without mediators. The mediators used were ferulic acid, coumaric acid and ABTS. It was observed that mediators as ABTS and ferulic acid were more successful enhancing PAH degradation.
Autores principais:Vipotnik, Ziva
Assunto:Soil degradation PAH Fungi Laccase Laccase-mediator system Degradação do solo Fungos Lacase Sistema mediador de lacase
Ano:2021
País:Portugal
Tipo de documento:tese de doutoramento
Tipo de acesso:acesso aberto
Instituição associada:Universidade do Minho
Idioma:inglês
Origem:RepositóriUM - Universidade do Minho

Registos relacionados

Registos relacionados