Enzymatic Oxidation of Aflatoxin M<sub>1</sub> in Milk Using CotA Laccase

Aflatoxin M<sub>1</sub> (AFM<sub>1</sub>) in milk poses a significant threat to human health. This study examined the capacity of <i>Bacillus licheniformis</i> CotA laccase to oxidize AFM<sub>1</sub>. The optimal conditions for the CotA laccase-catalyz...

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Main Authors: Yongpeng Guo, Hao Lv, Zhiyong Rao, Zhixiang Wang, Wei Zhang, Yu Tang, Lihong Zhao
Format: Article
Language:English
Published: MDPI AG 2024-11-01
Series:Foods
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Online Access:https://www.mdpi.com/2304-8158/13/22/3702
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author Yongpeng Guo
Hao Lv
Zhiyong Rao
Zhixiang Wang
Wei Zhang
Yu Tang
Lihong Zhao
author_facet Yongpeng Guo
Hao Lv
Zhiyong Rao
Zhixiang Wang
Wei Zhang
Yu Tang
Lihong Zhao
author_sort Yongpeng Guo
collection DOAJ
description Aflatoxin M<sub>1</sub> (AFM<sub>1</sub>) in milk poses a significant threat to human health. This study examined the capacity of <i>Bacillus licheniformis</i> CotA laccase to oxidize AFM<sub>1</sub>. The optimal conditions for the CotA laccase-catalyzed AFM<sub>1</sub> oxidation were observed at pH 8.0 and 70 °C, achieving an AFM<sub>1</sub> oxidation rate of 86% in 30 min. The <i>K</i>m and Vmax values for CotA laccase with respect to AFM<sub>1</sub> were 18.91 μg mL<sup>−1</sup> and 9.968 μg min<sup>−1</sup> mg<sup>−1</sup>, respectively. Computational analysis suggested that AFM<sub>1</sub> interacted with CotA laccase via hydrogen bonding and van der Waals interactions. Moreover, the oxidation products of AFM<sub>1</sub> mediated by CotA laccase were identified as the C3-hydroxy derivatives of AFM<sub>1</sub> by HPLC-FLD and UPLC-TOF/MS. Toxicological assessment revealed that the hepatotoxicity of AFM<sub>1</sub> was substantially reduced following oxidation by CotA laccase. The efficacy of CotA laccase in removing AFM<sub>1</sub> in milk was further tested, and the result showed that the enzyme agent achieved an AFM<sub>1</sub> removal rate of 83.5% in skim milk and 65.1% in whole milk. These findings suggested that CotA laccase was a novel AFM<sub>1</sub> oxidase capable of eliminating AFM<sub>1</sub> in milk. More effort is still needed to improve the AFM<sub>1</sub> oxidase activity of CotA laccase in order to shorten the processing time when applying the enzyme in the milk industry.
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spelling doaj-art-2f63084d71894bdc9f9227b9f78aa8a22024-11-26T18:04:51ZengMDPI AGFoods2304-81582024-11-011322370210.3390/foods13223702Enzymatic Oxidation of Aflatoxin M<sub>1</sub> in Milk Using CotA LaccaseYongpeng Guo0Hao Lv1Zhiyong Rao2Zhixiang Wang3Wei Zhang4Yu Tang5Lihong Zhao6College of Animal Science and Technology, Henan Agricultural University, Zhengzhou 450046, ChinaCollege of Animal Science and Technology, Henan Agricultural University, Zhengzhou 450046, ChinaCollege of Animal Science and Technology, Henan Agricultural University, Zhengzhou 450046, ChinaCollege of Animal Science and Technology, Henan Agricultural University, Zhengzhou 450046, ChinaCollege of Animal Science and Technology, Henan Agricultural University, Zhengzhou 450046, ChinaCollege of Animal Science and Technology, China Agricultural University, Beijing 100193, ChinaCollege of Animal Science and Technology, China Agricultural University, Beijing 100193, ChinaAflatoxin M<sub>1</sub> (AFM<sub>1</sub>) in milk poses a significant threat to human health. This study examined the capacity of <i>Bacillus licheniformis</i> CotA laccase to oxidize AFM<sub>1</sub>. The optimal conditions for the CotA laccase-catalyzed AFM<sub>1</sub> oxidation were observed at pH 8.0 and 70 °C, achieving an AFM<sub>1</sub> oxidation rate of 86% in 30 min. The <i>K</i>m and Vmax values for CotA laccase with respect to AFM<sub>1</sub> were 18.91 μg mL<sup>−1</sup> and 9.968 μg min<sup>−1</sup> mg<sup>−1</sup>, respectively. Computational analysis suggested that AFM<sub>1</sub> interacted with CotA laccase via hydrogen bonding and van der Waals interactions. Moreover, the oxidation products of AFM<sub>1</sub> mediated by CotA laccase were identified as the C3-hydroxy derivatives of AFM<sub>1</sub> by HPLC-FLD and UPLC-TOF/MS. Toxicological assessment revealed that the hepatotoxicity of AFM<sub>1</sub> was substantially reduced following oxidation by CotA laccase. The efficacy of CotA laccase in removing AFM<sub>1</sub> in milk was further tested, and the result showed that the enzyme agent achieved an AFM<sub>1</sub> removal rate of 83.5% in skim milk and 65.1% in whole milk. These findings suggested that CotA laccase was a novel AFM<sub>1</sub> oxidase capable of eliminating AFM<sub>1</sub> in milk. More effort is still needed to improve the AFM<sub>1</sub> oxidase activity of CotA laccase in order to shorten the processing time when applying the enzyme in the milk industry.https://www.mdpi.com/2304-8158/13/22/3702aflatoxin M<sub>1</sub>CotA laccaseoxidationmilk
spellingShingle Yongpeng Guo
Hao Lv
Zhiyong Rao
Zhixiang Wang
Wei Zhang
Yu Tang
Lihong Zhao
Enzymatic Oxidation of Aflatoxin M<sub>1</sub> in Milk Using CotA Laccase
Foods
aflatoxin M<sub>1</sub>
CotA laccase
oxidation
milk
title Enzymatic Oxidation of Aflatoxin M<sub>1</sub> in Milk Using CotA Laccase
title_full Enzymatic Oxidation of Aflatoxin M<sub>1</sub> in Milk Using CotA Laccase
title_fullStr Enzymatic Oxidation of Aflatoxin M<sub>1</sub> in Milk Using CotA Laccase
title_full_unstemmed Enzymatic Oxidation of Aflatoxin M<sub>1</sub> in Milk Using CotA Laccase
title_short Enzymatic Oxidation of Aflatoxin M<sub>1</sub> in Milk Using CotA Laccase
title_sort enzymatic oxidation of aflatoxin m sub 1 sub in milk using cota laccase
topic aflatoxin M<sub>1</sub>
CotA laccase
oxidation
milk
url https://www.mdpi.com/2304-8158/13/22/3702
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AT zhiyongrao enzymaticoxidationofaflatoxinmsub1subinmilkusingcotalaccase
AT zhixiangwang enzymaticoxidationofaflatoxinmsub1subinmilkusingcotalaccase
AT weizhang enzymaticoxidationofaflatoxinmsub1subinmilkusingcotalaccase
AT yutang enzymaticoxidationofaflatoxinmsub1subinmilkusingcotalaccase
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