Key Laboratory of Molecular Biophysics of MOE, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China.
Key Lab of Green Chemical Technology & High Efficient Energy Saving of Hebei Province, Hebei University of Technology, Tianjin, China.
PLoS One. 2018 Aug 23;13(8):e0202440. doi: 10.1371/journal.pone.0202440. eCollection 2018.
The white-rot fungus Cerrena unicolor BBP6 produced up to 243.4 U mL-1 laccase. A novel laccase isoform LacA was purified; LacA is a homodimer with an apparent molecular mass of 55 kDa and an isoelectric point of 4.7. Its optimal pH was 2.5, 4.0, and 5.5 when 2, 2'-Azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS), guaiacol, and 2, 6-dimethoxyphenol (2, 6-DMP) were used as the substrates, respectively. The optimal temperature was 60°C for ABTS and 80°C for both guaiacol and 2, 6-DMP. LacA retained 82-92% activity when pH was greater than 4 and 42%-92% activity at or below 50°C. LacA was completely inhibited by 0.1 mM L-cysteine, 1 mM Dithiothreitol, and 10 mM metal ions, Ca2+, Mg2+ and Co2+. LacA had good affinity for ABTS, with a Km of 49.1 μM and a kcat of 3078.9 s-1. It decolorized synthetic dyes at 32.3-87.1%. In the presence of 1-hydroxybenzotriazole (HBT), LacA decolorized recalcitrant dyes such as Safranine (97.1%), Methylene Blue (98.9%), Azure Blue (96.6%) and simulated textile effluent (84.6%). With supplemented manganese peroxidase (MnP), Mn2+ and HBT, the purified LacA and BBP6 fermentation broth showed great potential in denim bleaching, with an up to 5-fold increase in reflectance values.
白腐真菌 Cerrena unicolor BBP6 可产高达 243.4 U mL-1 的漆酶。一种新型漆酶同工酶 LacA 被纯化；LacA 是一种具有 55 kDa 表观分子量和 4.7 的等电点的同源二聚体。当使用 2,2'-联氮双（3-乙基苯并噻唑啉-6-磺酸）（ABTS）、愈创木酚和 2,6-二甲氧基苯酚（2,6-DMP）作为底物时，其最适 pH 值分别为 2.5、4.0 和 5.5。最适温度分别为 60°C（ABTS）和 80°C（愈创木酚和 2,6-DMP）。LacA 在 pH 值大于 4 时保留 82-92%的活性，在 50°C 或以下时保留 42-92%的活性。0.1 mM L-半胱氨酸、1 mM Dithiothreitol 和 10 mM 金属离子 Ca2+、Mg2+和 Co2+可完全抑制 LacA 的活性。LacA 对 ABTS 具有良好的亲和力，Km 值为 49.1 μM，kcat 值为 3078.9 s-1。它可使合成染料脱色 32.3-87.1%。在 1-羟基苯并三唑（HBT）存在下，LacA 可使难处理的染料如藏红（97.1%）、亚甲蓝（98.9%）、Azure Blue（96.6%）和模拟纺织废水（84.6%）脱色。在补充锰过氧化物酶（MnP）、Mn2+和 HBT 的情况下，纯化的 LacA 和 BBP6 发酵液在牛仔布漂白中显示出巨大的潜力，反射率值提高了 5 倍。
