Biocatalysts immobilization onto nanostructured supports with application in the biotransformation of emerging pollutants
Garcia Morales, Raul
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Biotransformation of emerging pollutants in water samples using biocatalysts such as laccases, provides an environmentally attractive alternative to complement conventional wastewater treatments. However, loss and inactivation of enzymes are challenges to solve for their potential use in water treatment applications. The work included in this thesis explores the development of new biocatalyst using a new laccase from Pycnoporus sanguineus CS43 strain. First, the biotransformation of contaminants with laccases in free form was carried out to demonstrate their removal potential. Secondly, through enzyme immobilization using nanomaterials as supports to improve the stability and catalytic properties of laccase enzymes. In order to demonstrate the biotransformation potential of laccases for emerging pollutants, two studies were carried out, in which the effect of enzymes in their free form was analyzed. First, a synthetic matrix was used, followed by using groundwater as a real matrix. The first work evidenced an enhanced biotransformation capability to remove common emerging pollutants such as bisphenol A, 4-nonylphenol, 17-α-ethynylestradiol and triclosan, achieving biotransformation efficiencies of 89–100 % using synthetic samples. In groundwater, biotransformation ranged from 55 to 93 %. The second study also focused in proving the biocatalytic ability of laccases, in this case biotransformation in synthetic samples ranged from 50 – 97 % for diclofenac, β-Naphthol, 2,4 dichlorophenol and 5,7-diiodo-8-hydroxyquinoline, while for groundwater laccases biotransformed more than 53% for all compounds. Enzyme immobilization onto nanomaterials was achieved using the covalent approach. Process optimization and later studies demonstrated that the proposed procedure using 3-aminopropyltriethoxysilane (APTES) as coupling agent and the cross-linker glutaraldehyde (GLU) as a laccase binder, can enhance inherent properties of laccase enzymes such as high thermostability and pH stability Furthermore, the biocatalyst was assessed in the biotransformation of emerging pollutants such as acetaminophen and diclofenac showing more than 90% biotransformation in synthetic and real samples. Consequently, due to the promising results obtained in the aforementioned studies, where the enzymatic treatment was evaluated under mild reaction condition, this biocatalytic approach represents a good alternative in the treatment of organic pollutants in water samples.
- Carta Autorización Tesis RaulGM220219.pdf
- Carta de Autorizaciòn
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