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Abstract：
Laccases are industrially relevant enzymes that have gained great biotechnological importance. To date, most are of fungal and mesophilic origin; however, enzymes from extremophiles possess an even greater potential to withstand industrial conditions. In this study, we evaluate the potential of a recombinant spore-coat laccase from the thermoalkaliphilic bacterium Bacillus sp. FNT (FNTL) to biodegrade antibiotics from the tetracycline, β-lactams, and fluoroquinolone families. This extremozyme was previously characterized as being thermostable and highly active in a wide range of temperatures (20-90 °C) and very versatile towards several structurally different substrates, including recalcitrant environmental pollutants such as PAHs and synthetic dyes. First, molecular docking analyses were employed for initial ligand affinity screening in the modeled active site of FNTL. Then, the in silico findings were experimentally tested with four highly consumed antibiotics, representatives of each family: tetracycline, oxytetracycline, amoxicillin, and ciprofloxacin. HPLC results indicate that FNTL with help of the natural redox mediator acetosyringone, can efficiently biodegrade 91, 90, and 82% of tetracycline (0.5 mg mL-1) in 24 h at 40, 30, and 20 °C, respectively, with no apparent ecotoxicity of the products on E. coli and B. subtilis. These results complement our previous studies, highlighting the potential of this extremozyme for application in wastewater bioremediation.
摘要：
漆酶是工业相关的酶,其已经获得了极大的生物技术重要性。迄今为止,大多数是真菌和嗜温的起源；然而，来自极端微生物的酶具有更大的潜力来承受工业条件。在这项研究中,我们评估了来自热亲碱性细菌芽孢杆菌的重组孢子漆酶的潜力。FNT(FNTL)从四环素中生物降解抗生素，β-内酰胺,和氟喹诺酮家族。这种极端酶以前的特征是在很宽的温度范围内（20-90°C）具有热稳定性和高活性，并且对几种结构不同的底物非常通用，包括顽固的环境污染物，如多环芳烃和合成染料。首先,分子对接分析用于FNTL建模活性位点的初始配体亲和筛选。然后，使用四种高度消耗的抗生素进行了实验测试，每个家庭的代表：四环素，土霉素,阿莫西林,还有环丙沙星.HPLC结果表明，FNTL借助天然氧化还原介质乙酰丁香酮，可以在40、30和20°C下24小时内有效地生物降解91、90和82％的四环素（0.5mgmL-1），分别,产品对大肠杆菌和枯草芽孢杆菌没有明显的生态毒性。这些结果补充了我们以前的研究，强调了这种极端酶在废水生物修复中的应用潜力。
