Zhang Yanzhou, Li Xunhang, Hao Zhikui, Xi Ruchun, Cai Yujie, Liao Xiangru
The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi, 214122, China.
The Bioscience and Engineering College, Jiangxi Agriculture University, Nanchang, 330045, China.
PLoS One. 2016 Jun 30;11(6):e0158351. doi: 10.1371/journal.pone.0158351. eCollection 2016.
For the more efficient detoxification of phenolic compounds, a promising avenue would be to develop a multi-enzyme biocatalyst comprising peroxidase, laccase and other oxidases. However, the development of this multi-enzyme biocatalyst is limited by the vulnerability of fungal laccases and peroxidases to hydrogen peroxide (H2O2)-induced inactivation. Therefore, H2O2-resistant peroxidase and laccase should be exploited. In this study, H2O2-stable CotA and YjqC were isolated from the outer coat of Bacillus altitudinis SYBC hb4 spores. In addition to the thermal and alkali stability of catalytic activity, CotA also exhibited a much higher H2O2 tolerance than fungal laccases from Trametes versicolor and Trametes trogii. YjqC is a sporulation-related manganese (Mn) catalase with striking peroxidase activity for sinapic acid (SA) and sinapine (SNP). In contrast to the typical heme-containing peroxidases, the peroxidase activity of YjqC was also highly resistant to inhibition by H2O2 and heat. CotA could also catalyze the oxidation of SA and SNP. CotA had a much higher affinity for SA than B. subtilis CotA. CotA and YjqC rendered from B. altitudinis spores had promising laccase and peroxidase activities for SA and SNP. Specifically, the B. altitudinis spores could be regarded as a multi-enzyme biocatalyst composed of CotA and YjqC. The B. altitudinis spores were efficient for catalyzing the degradation of SA and SNP in rapeseed meal. Moreover, efficiency of the spore-catalyzed degradation of SA and SNP was greatly improved by the presence of 15 mM H2O2. This effect was largely attributed to synergistic biocatalysis of the H2O2-resistant CotA and YjqC toward SA and SNP.
为了更有效地解毒酚类化合物，一个有前景的途径是开发一种包含过氧化物酶、漆酶和其他氧化酶的多酶生物催化剂。然而，这种多酶生物催化剂的开发受到真菌漆酶和过氧化物酶易受过氧化氢（H2O2）诱导失活的限制。因此，应开发耐H2O2的过氧化物酶和漆酶。在本研究中，从高地芽孢杆菌SYBC hb4孢子的外层分离出了H2O2稳定的CotA和YjqC。除了催化活性的热稳定性和碱稳定性外，CotA对H2O2的耐受性也比云芝和栓菌的真菌漆酶高得多。YjqC是一种与孢子形成相关的锰（Mn）过氧化氢酶，对芥子酸（SA）和芥子碱（SNP）具有显著的过氧化物酶活性。与典型的含血红素过氧化物酶不同，YjqC的过氧化物酶活性对H2O2和热的抑制也具有高度抗性。CotA也可以催化SA和SNP的氧化。CotA对SA的亲和力比枯草芽孢杆菌的CotA高得多。高地芽孢杆菌孢子中的CotA和YjqC对SA和SNP具有有前景的漆酶和过氧化物酶活性。具体而言，高地芽孢杆菌孢子可被视为由CotA和YjqC组成的多酶生物催化剂。高地芽孢杆菌孢子对催化菜籽粕中SA和SNP的降解是有效的。此外，15 mM H2O2的存在大大提高了孢子催化SA和SNP降解的效率。这种效应很大程度上归因于耐H2O2的CotA和YjqC对SA和SNP的协同生物催化作用。
