Fungal laccases are industrially important inducible enzymes extensively used in the delignification of lignocellulosics, detoxification of environmental wastes and decolorization of textile dyes. The discovery of new inducers is crucial for laccase productivity by filamentous fungi. In this study, a novel laccase-producing strain S8 from a bambusicolous fungus Shiraia bambusicola was identified by using 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate) as laccase secretion indicator and native polyacrylamide gel electrophoresis. The corresponding full-length cDNA of laccase was cloned and characterized. The effect of lanthanum (LaCl₃) on extracellular laccase activity was tested at the concentration from 0.2 to 2.0 g/L and at different addition time (day 1–4) in the mycelium culture. In the presence of 1.0 g/L La³⁺ at the beginning of the mycelium cultures, the highest laccase activity (2.7 × 10⁴ U/L) is reached after 10 days of cultivation, about tenfold higher compared with non-induced cultures. La³⁺ is shown to be a very strong inducer for fungal laccase activity with no inhibitory effect on fungal growth at the optimized concentration. In vivo, La³⁺ added to the mycelium culture not only promotes a continuous and high expression of laccase gene (lcc1), but also induces a rapid generation of signaling molecules including reactive oxygen species (ROS) and nitric oxygen (NO). Both the NO donor sodium nitroprusside (SNP) and exogenous hydrogen peroxide (H₂O₂) potentiate La³⁺-induced laccase activity and increase membrane permeability of hyphal cells. Moreover, the scavengers such as 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO) for NO and vitamin C for ROS suppress the induction. These results suggest that these signals can mediate La³⁺-induced laccase biosynthesis and its secretion. Our study provides a basis for understanding the induction mechanism of La³⁺ on laccase and a practical strategy for enhanced fungal laccase production.

真菌漆酶是工业上重要的诱导酶，广泛用于木质纤维素的脱木质素、环境废物的解毒和纺织染料的脱色。新诱导剂的发现对于丝状真菌的漆酶生产力至关重要。在这项研究中，通过使用 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) 作为漆酶分泌指示剂和天然聚丙烯酰胺凝胶电泳鉴定了来自竹子真菌Shiraia bambusicola的新型漆酶生产菌株 S8。相应的漆酶全长cDNA被克隆和表征。镧（LaCl ₃) 在菌丝体培养物中以 0.2 至 2.0 g/L 的浓度和不同的添加时间（第 1-4 天）测试细胞外漆酶活性。在菌丝体培养开始时存在 1.0 g/L La ³⁺的情况下，培养10 天后达到最高漆酶活性（2.7 × 10 ^{4 U/L），与未诱导培养物相比高出约 10 倍。}La ³⁺被证明是一种非常强的真菌漆酶活性诱导剂，在优化浓度下对真菌生长没有抑制作用。在体内，添加到菌丝体培养物中的La ³⁺不仅可以促进漆酶基因（lcc1)，但也诱导信号分子的快速生成，包括活性氧 (ROS) 和一氧化氮 (NO)。NO 供体硝普钠 (SNP) 和外源性过氧化氢 (H ₂ O ₂ ) 均可增强 La ³⁺诱导的漆酶活性并增加菌丝细胞的膜通透性。此外，清除剂如 2-(4-羧基苯基)-4,4,5,5-四甲基咪唑啉-1-氧基-3-氧化物 (cPTIO) 用于 NO 和维生素 C 用于 ROS 抑制诱导。这些结果表明这些信号可以介导La ³⁺诱导的漆酶生物合成及其分泌。我们的研究为理解La ^{3+的诱导机制提供了基础。}关于漆酶和提高真菌漆酶生产的实用策略。