title: Aflatoxin B₁ and M₁ Degradation by Lac2 from Pleurotus pulmonarius and Redox Mediators.
abstract: Laccases (LCs) are multicopper oxidases that find application as versatile biocatalysts for the green bioremediation of environmental pollutants and xenobiotics. In this study we elucidate the degrading activity of Lac2 pure enzyme form Pleurotus pulmonarius towards aflatoxin B₁ (AFB₁) and M₁ (AFM₁). LC enzyme was purified using three chromatographic steps and identified as Lac2 through zymogram and LC-MS/MS. The degradation assays were performed in vitro at 25 °C for 72 h in buffer solution. AFB₁ degradation by Lac2 direct oxidation was 23%. Toxin degradation was also investigated in the presence of three redox mediators, (2,2'-azino-bis-[3-ethylbenzothiazoline-6-sulfonic acid]) (ABTS) and two naturally-occurring phenols, acetosyringone (AS) and syringaldehyde (SA). The direct effect of the enzyme and the mediated action of Lac2 with redox mediators univocally proved the correlation between Lac2 activity and aflatoxins degradation. The degradation of AFB₁ was enhanced by the addition of all mediators at 10 mM, with AS being the most effective (90% of degradation). AFM₁ was completely degraded by Lac2 with all mediators at 10 mM. The novelty of this study relies on the identification of a pure enzyme as capable of degrading AFB₁ and, for the first time, AFM₁, and on the evidence that the mechanism of an effective degradation occurs via the mediation of natural phenolic compounds. These results opened new perspective for Lac2 application in the food and feed supply chains as a biotransforming agent of AFB₁ and AFM₁.
authors: Institute of Sciences of Food Production, National Research Council of Italy (CNR), via Amendola 122/O, Bari 70126, Italy. martina.loi@ispa.cnr.it.|Department of Economics, University of Foggia, via Napoli 25, Foggia 71122, Italy. martina.loi@ispa.cnr.it.
authors: Martina
authors: M
authors: Loi
authors: Institute of Sciences of Food Production, National Research Council of Italy (CNR), via Amendola 122/O, Bari 70126, Italy. francesca.fanelli@ispa.cnr.it.
authors: Francesca
authors: F
authors: Fanelli
authors: Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria, Complesso Universitario, SP Monserrato-Sestu Km 0.700, Monserrato 09042, Italy. pzucca@unica.it.
authors: Paolo
authors: P
authors: Zucca
authors: Institute of Sciences of Food Production, National Research Council of Italy (CNR), via Amendola 122/O, Bari 70126, Italy. vania.liuzzi@ispa.cnr.it.
authors: Vania C
authors: VC
authors: Liuzzi
authors: Institute of Sciences of Food Production, National Research Council of Italy (CNR), via Amendola 122/O, Bari 70126, Italy. laura.quintieri@ispa.cnr.it.
authors: Laura
authors: L
authors: Quintieri
authors: Institute of Sciences of Food Production, National Research Council of Italy (CNR), via Amendola 122/O, Bari 70126, Italy. teresa.cimmarusti@ispa.cnr.it.|Department of Economics, University of Foggia, via Napoli 25, Foggia 71122, Italy. teresa.cimmarusti@ispa.cnr.it.
authors: Maria T
authors: MT
authors: Cimmarusti
authors: Institute of Sciences of Food Production, National Research Council of Italy (CNR), via Amendola 122/O, Bari 70126, Italy. linda.monaci@ispa.cnr.it.
authors: Linda
authors: L
authors: Monaci
authors: Institute of Sciences of Food Production, National Research Council of Italy (CNR), via Amendola 122/O, Bari 70126, Italy. miriam.haidukowski@ispa.cnr.it.
authors: Miriam
authors: M
authors: Haidukowski
authors: Institute of Sciences of Food Production, National Research Council of Italy (CNR), via Amendola 122/O, Bari 70126, Italy. antonio.logrieco@ispa.cnr.it.
authors: Antonio F
authors: AF
authors: Logrieco
authors: Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria, Complesso Universitario, SP Monserrato-Sestu Km 0.700, Monserrato 09042, Italy. sanjust@unica.it.
authors: Enrico
authors: E
authors: Sanjust
authors: Institute of Sciences of Food Production, National Research Council of Italy (CNR), via Amendola 122/O, Bari 70126, Italy. giuseppina.mule@ispa.cnr.it.
authors: Giuseppina
authors: G
authors: Mulè
mesh_terms: D000098:Acetophenones / Q000494:pharmacology; D016604:Aflatoxin B1 / Q000378:metabolism*; D016607:Aflatoxin M1 / Q000378:metabolism*; D001547:Benzaldehydes / Q000494:pharmacology; D052160:Benzothiazoles / Q000494:pharmacology; D001673:Biodegradation, Environmental / Q000187:drug effects; D005516:Food Microbiology; D005656:Fungal Proteins / Q000378:metabolism*; D042845:Laccase / Q000378:metabolism*; D010084:Oxidation-Reduction; D020076:Pleurotus / Q000145:classification / Q000201:enzymology*; D059748:Proteolysis; D013379:Substrate Specificity; D013451:Sulfonic Acids / Q000494:pharmacology; D013997:Time Factors
chemical_list: D000098:Acetophenones; D001547:Benzaldehydes; D052160:Benzothiazoles; D005656:Fungal Proteins; D013451:Sulfonic Acids; C002502:2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid; C069665:syringaldehyde; D016607:Aflatoxin M1; C051667:acetosyringone; D016604:Aflatoxin B1; D042845:Laccase
keywords: Pleurotus; aflatoxin B1; aflatoxin M1; biodegradation; laccase; mycotoxins; redox mediators