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Covalent immobilization of laccase on citric acid functionalized micro-biochars derived from different feedstock and removal of diclofenac.

Lonappan, Linson; Liu, Yuxue; Rouissi, Tarek; Pourcel, Florent; Brar, Satinder Kaur; Verma, Mausam P.; Surampalli, Rao Y. (2018). Covalent immobilization of laccase on citric acid functionalized micro-biochars derived from different feedstock and removal of diclofenac. Chemical Engineering Journal , vol. 351 . p. 985-994. DOI: 10.1016/j.cej.2018.06.157.

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Résumé

Immobilization of enzymes on the solid supports can improve the stability as well as catalytic properties of enzymes. In this study, biochar derived from various feedstocks were used as immobilization support considering biochars carbon negative as well as sustainable properties. Partially purified (concentrated) crude laccase was covalently immobilized onto pine wood (BC-PW), pig manure (BC-PM) and almond shell (BC-AS) micro-biochars using optimized 5% w/v glutaraldehyde. Moreover, citric acid pretreatment improved the laccase binding capacity of all the micro-biochars and the highest laccase binding of 40.2 ± 1.8 U g⁻¹ was observed with BC-PM in comparison with raw BC-PM (34.1 ± 1.1 U g⁻¹). The enhanced binding of laccase on BC-PM over wood derived biochars was attributed to the higher surface area (46.1 m² g⁻¹) of BC-PM. Moreover, feedstock selection as well as a method of production influenced the biochar physicochemical properties such as surface area and consequently, different biochars showed various laccase immobilization efficiencies. BC-PW showed better pH, thermal, storage, and operational stability, compared with BC-AS and BC-PM. While applying the laccase bound micro-biochar, complete removal was observed in 2 h under batch mode with 0.5 g of laccase bound BC-PM at an environmentally relevant concentration of 500 µg L⁻¹ in wastewater effluent. About 40% of the laccase activity was retained with all the laccase-bound micro-biochars after 5 cycles of diclofenac treatment.

Type de document: Article
Mots-clés libres: covalent immobilization; biochar; laccase; citric acid; enzymes stability; diclofenac
Centre: Centre Eau Terre Environnement
Date de dépôt: 28 nov. 2018 15:38
Dernière modification: 28 nov. 2018 15:38
URI: http://espace.inrs.ca/id/eprint/7720

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