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Title: Enhanced biocatalytic sustainability of laccase by immobilization on functionalized carbon nanotubes/polysulfone membranes
Author: Costa, João B.
Lima, Maria J.
Sampaio, Maria J.
Neves, Márcia C.
Faria, Joaquim L.
Morales-Torres, Sergio
Tavares, Ana P. M.
Silva, Cláudia G.
Keywords: Multi-walled carbon nanotubes (CNTs)
Chemical functionalization
CNTs-based polysulfone membranes
Wastewater treatment
Issue Date: 1-Jan-2019
Publisher: Elsevier
Abstract: Chemically functionalized multi-walled carbon nanotubes (CNTs) are used as carriers for laccase immobilization. In this work, CNTs were modified using different approaches with a combination of methods involving hydrothermal oxidation with nitric acid, treatment with 3-aminopropyltriethoxysilane, glutaraldehyde, N-ethyl-N-(3-(dimethylamino)-propyl) carbodiimide hydrochloride and N-hydroxysuccinimide. The enzyme immobilization efficiency and recovered activity were evaluated towards 2,2′-azino-bis(3-ethylbenzathiazoline-6-sulfonic acid) biocatalytic oxidation. The best compromise between immobilization efficiency and recovered activity was obtained using the CNTs functionalized with 0.3 M HNO3, treated with N-ethyl-N-(3-(dimethylamino)propyl) carbodiimide hydrochloride and N-hydroxysuccinimide. This catalyst also showed the best thermal stability (at 50 and 60 °C). The bioconjugate based on this material was characterized by vibrational spectroscopies (FTIR and Raman) and by N2 adsorption. The results from reutilization tests showed that laccase activity was kept above 65% of its initial value after five consecutive cycles of reuse. The biocatalytic performance of the immobilized enzyme was evaluated for the degradation of a mixture of phenolic compounds in water containing phenol, resorcinol, 4-methoxyphenol and 4-chlorophenol. As means of cost efficient to enzyme reutilization, laccase was immobilized over polysulfone membranes blended with the functionalized CNTs and studied in the degradation of 4-methoxyphenol.
Peer review: yes
DOI: 10.1016/j.cej.2018.08.178
ISSN: 1385-8947
Appears in Collections:CICECO - Artigos

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