Bracco, Pierangiola

Laurenti, Enzo

Magnacca, Giuliana

English

Institutional Research Information System University of Turin

N°817 / OCTOPIC(s) : Renewable carbon / Biomass conversion / Valorization of waste / Catalytic systemsSilica-based monoliths functionalized with peroxidase as bifunctional tools forindustrial and environmental applicationsAUTHORSEnzo LAURENTI / UNIVERSITÀ DI TORINO, VIA PIETRO GIURIA 7, TORINOGiuliana MAGNACCA / UNIVERSITÀ DI TORINO, VIA PIETRO GIURIA 7, TORINOPierangiola BRACCO / UNIVERSITÀ DI TORINO, VIA PIETRO GIURIA 7, TORINOPURPOSE OF THE ABSTRACTThe high concentration of wastes in urban areas and the modern recycling policies have allowed the collection ofbio-organic matter in well-confined spaces, favouring the possible utilization of urban biowastes as source ofenergy and materials. The lignin-like fraction obtained after the composting process of urban biowastes contains a lot of organicsubstances similar to humic acids. In particular, from the humid fraction of urban wastes a mixture of solublebio-based substances (BBS) can be isolated [1]. These substances are constituted by long aliphatic carbon chains, partially substituted by aromatic rings andcontaining several functional groups. The potential use of BBS deriving from food waste as a cost-effective sourceof bio-based products was also reported [2]. A non-exhausted list of potential fields of application for BBSincludes: textile industry, detergency, agriculture, polluted soil washing, wastewater treatment and materialscience. The possibility to develop environmental friend alternative to existing materials induced us to study the employ ofBBS in different kinds of systems useful in removal of water pollutants. In particular, we reported the preparationand characterization of stable and effective biocatalysts obtained by covalent bonding of Soybean peroxidase onsilica monoliths prepared from commercial siliceous powders by using BBS as binding agent [3-4]. This way it ispossible to combine the environmentally friend reuse of waste to prepare technological tools with the efficiencyand the affordability of reusable enzymes. In this work we explored the efficiency of these systems in the removal of water pollutants and show as it ispossible to obtain promising results taking advantage of the co-operative effect of the adsorbing properties of thematerial and the enzymatic catalysis. Moreover, the immobilization on monoliths give to Soybean peroxidase anunusual resistance to the thermic denaturation permitting its use in a wider set of experimental conditions.Several monoliths were synthesized (figure 1) with a previously reported procedure [2] by mixing BBS and twosilica powders with different hydrophilicity (Sipernat320 and Aerosil300 by Evonik) in different percentage. Thesamples were initially characterized by nitrogen adsorption in order to determine surface area and porosity. Thentheir breaking load was measured in order to assess their mechanical resistance in case of practical applications.Furthermore their adsorption properties were studied by adsorption microcalorimetry and UV-visible spectroscopy.The results show as the adsorption properties depend both from the relative amount of the two silicas and thedifferent surface properties induced by the presence of BBS. In fact, the adsorption properties of the monoliths arestronger than those of the silica powders alone.Some monoliths, chosen on the basis of their adsorption properties, were functionalized with Soybean peroxidaseby means of the aminopropyltriethoxysilane/glutaraldehyde method [3,4]. The catalytic properties of thesebiocatalysts were successively tested with different substrates and in the depuration of two real wastewaterssupplied by a textile fabric. The results show as the enzymatic action contributes to the decolourization of the testsolutions and, in the presence of a mixture of coloured waste, the total bleaching is guaranteed by the join actionof surface adsorption and enzymatic degradation (figure 2). Finally, the thermal denaturation of a biocatalyst was studied and the results compared with the modification in theprotein conformation observed by FTIR spectroscopy. Surprisingly, even after heating at 150°C, immobilizedSoybean peroxidase maintain its secondary structure unchanged and retains a part of its initial activity.FIGURESFIGURE 1Silica-based monolithsImage of monoliths synthesized by BBS and silicapowder. The scale is in centimeters.FIGURE 2Bleaching of a real wasteProgressive decolourization of a textile fabric wastetreated with functionalized monoliths.KEYWORDSmonolith | peroxidase | wastewater | adsorptionBIBLIOGRAPHY[1] montoneri, e., boffa, v., savarino, p., perrone, d., ghezzo, m., montoneri, c., mendichi, r., waste manage. 2011,31, 10-17.[2] avetta, p., bella, f., bianco prevot, a., laurenti, e., montoneri, e., arques, a., carlos, l., ACS sust. chem. eng.2013, 1, 1545-1550[3] magnacca, g., laurenti, e., vigna, e., franzoso, f., tomasso, l., montoneri, e., boffa, v., process. biochem. 2012,47, 2025-2031.[4] calza, p., zacchigna, d., laurenti, e., environ. sci. pollut. res. 2016, 23, 23742-23749.

Silica-based monoliths functionalized with peroxidase as bifunctional tools for industrial and environmental applications

https://iris.unito.it/bitstream/2318/1681660/1/abstract-817-574BD.pdf

Silica-based monoliths functionalized with peroxidase as bifunctional tools for industrial and environmental applications

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