Immobilisation of laccase on Eupergit supports and its application for the removal of endocrine disrupting chemicals in a packed-bed reactor

Abstract

Laccase from Myceliophthora thermophila was covalently immobilised on Eupergit C and Eupergit C 250L yielding specific activities of up to 17 and 80 U/g, respectively. Due to its superior activity, Eupergit C 250L was chosen for further research. The somewhat lower catalytic efficiency (based on the ratio between the turnover number and the Michaelis constant, k cat /K M ) of the immobilised enzyme in comparison with that of the free enzyme was balanced by its increased stability and broader operational window related to temperature and pH. The feasibility of the immobilised laccase was tested by using a packed bed reactor (PBR) operating in consecutive cycles for the removal of Acid Green 27 dye as model substrate. High degrees of elimination were achieved (88, 79, 69 and 57% in 4 consecutive cycles), while the levels of adsorption on the support varied from 18 to 6%, proving that dye removal took place mainly due to the action of the enzyme. Finally, a continuous PBR with the solid biocatalyst was applied for the treatment of a solution containing the following endocrine disrupting chemicals: estrone (E1), 17b-estradiol (E2) and 17a-ethinylestradiol (EE2). At steady-state operation, E1 was degraded by 65% and E2 and EE2 were removed up to 80% and only limited adsorption of these compounds on the support, between 12 and 22%, was detected. In addition, a 79% decrease in estrogenic activity was detected in the effluent of the enzymatic reactor while only 14% was attained by inactivated laccase.

Fungal Bioremediation of Emerging Micropollutants in Municipal Wastewaters

“…For example, the treatment of estrone and estradiol was carried out with laccases from M. thermophile using up to 2,000 U/l. The minimal effective enzymatic concentration was found to range from 100 to 500 U/l with no mediator need (Lloret et al 2012a). These values are coherent with those observed by Spina and collaborators (2015): in the tested range (10-500 U/l) the minimal effective concentration for 18 compounds was usually 100 U/l.…”

“…A similar induction was noticed after phthalates, BPA and NP addition to a T. versicolor culture: the secreted enzymatic pattern further degraded the molecules tested (Kim et al 2008). Cheong and collaborators (2006) (Auriol et al 2008, Kim and Nicell 2006a, Lloret et al 2010, Lloret et al 2012a, Lloret et al 2013, Murugesan et al 2010, Songulashvili et al 2012, Torres-Duarte et al 2012, Tran et al 2013). Transformation rates of many compounds were not always coherent among evidences present in literature.…”

“…A number of materials complied these requirements, successfully supported laccases for micropollutants removal: nylon membranes (Diano et al 2007), silica particles (Gasser et al 2014b, Songulashvili et al 2012, Eupergit carriers (Lloret et al 2012a), TiO 2 nanoparticles (Hou et al 2014), glass beads (Macellaro et al 2014) and cross-linked enzyme aggregates (Cabana et al 2007c) among others.…”

Laccase Immobilization on Poly(p-Phenylenediamine)/Fe3O4 Nanocomposite for Reactive Blue 19 Dye Removal

“…First, the enzyme may be inactivated or inhibited by the accumulation of dye degradation products [48]. Second, mass transfer limitations may be induced by dye or metabolite adsorption to the PpPD/Fe3O4 carrier [49,50]. Moreover, during the catalytic reaction, some of the Fe3O4 nanoparticles were found to be released from the PpPD/Fe3O4 nanocomposite due to vigorous stirring, leading to a reduction in the magnetic force of the carriers.…”

Enzyme Initiated Radical Polymerizations

“…Likewise halophenols [178][179][180][181][182] bisphenol A, [183][184][185] various hormones and so-called endocrine disrupting compounds [186][187][188] or even TNT [189,190] have been reported. Non-phenolic compounds may be ‗inactivated' using the LMS or PMS strategy [36,[191][192][193][194][195][196][197][198].…”