A Thermostable Metal-Tolerant Laccase with Bioremediation Potential from a Marine-Derived Fungus
A Thermostable Metal-Tolerant Laccase with Bioremediation Potential from a Marine-Derived Fungus
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DOI：
10.1007/s10126-009-9187-0
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发表时间：
2009-12-01
影响因子：
3
通讯作者：
Raghukumar, Chandralata
中科院分区：
文献类型：
--
作者：
D'Souza-Ticlo, Donna;Sharma, Deepak;Raghukumar, Chandralata
漆酶是一种氧化还原酶，在生物修复中起着重要作用。虽然海洋真菌是工业应用的潜在酶源，但对它们的探索还不够充分。从腐烂的红树林中分离到真菌MTCC 5159，根据28S的D1/D2区和18S核糖体DNA序列鉴定为Cerrena unicolor，对几种合成染料进行了脱色处理。部分纯化的漆酶在30℃条件下，24 h内可使甘蔗渣纸浆中木质素的含量降低36%，漆酶是在低氮半浓海水培养基中产生的主要木质素降解酶（类似24000 U L-1）。得到了三种不同分子质量的漆酶，Lac I、Lac II和Lac III。每一种，通过阴离子交换色谱进一步分解成四种同工酶。主要同工酶Lac IId的n端氨基酸序列与担子菌的漆酶具有70-85%的同源性。其n链聚糖含量为17%。Lac IId的最适pH为3℃，最适温度为70℃，70℃下的半衰期为90 min。该酶在pH值为9时最稳定，在50A℃和60A℃温度下180min仍能保持60%以上的活性。1 mmol的Pb、Fe、Ni、Li、Co和Cd对酶无抑制作用。本文首次报道了从具有工业应用潜力的海洋真菌中提取的耐热耐金属漆酶的特性。
Laccase, an oxidoreductive enzyme, is important in bioremediation. Although marine fungi are potential sources of enzymes for industrial applications, they have been inadequately explored. The fungus MTCC 5159, isolated from decaying mangrove wood and identified as Cerrena unicolor based on the D1/D2 region of 28S and the 18S ribosomal DNA sequence, decolorized several synthetic dyes. Partially purified laccase reduced lignin content from sugarcane bagasse pulp by 36% within 24 h at 30A degrees C. Laccase was the major lignin-degrading enzyme (similar to 24,000 U L-1) produced when grown in low-nitrogen medium with half-strength seawater. Three laccases, Lac I, Lac II, and Lac III, of differing molecular masses were produced. Each of these, further resolved into four isozymes by anion exchange chromatography. The N-terminal amino acid sequence of the major isozyme, Lac IId showed 70-85% homology to laccases from basidiomycetes. It contained an N-linked glycan content of 17%. The optimum pH and temperature for Lac IId were 3 and 70A degrees C, respectively, the half-life at 70A degrees C being 90 min. The enzyme was most stable at pH 9 and retained > 60% of its activity up to 180 min at 50A degrees C and 60A degrees C. The enzyme was not inhibited by Pb, Fe, Ni, Li, Co, and Cd at 1 mmol. This is the first report on the characterization of thermostable metal-tolerant laccase from a marine-derived fungus with a potential for industrial application.