Abstract

A novel extracellular lignin peroxidase (LiP) has been produced (65 U/mL) in potato dextrose broth (PDB)-optimized media by a white-rot Agaricomycetes fungus strain KB-DZ15 newly isolated from dead deciduous trees at Zimoula Forest (Tizi-Ouzou, Algeria). This strain was identified as Phlebia radiata based on internal transcribed spacer (ITS) rDNA gene sequencing. The peroxidase enzyme (called LiP PR40) was purified and characterised. The matrix-assisted laser desorption-ionization – time of flight mass spectrometry (MALDI-TOF/MS) analysis revealed that LiP PR40 enzyme was a monomer with a molecular mass of 40,125.31 Da. The 25 N-terminal residue sequence of LiP PR40 showed high similarity with those of fungi LiPs. Interestingly, LiP PR40 presents premium activity at pH 3 and 80 °C with specific activity and Reinheitzahl (RZ) level of 510 U/mg and 2.81, respectively. Furthermore, it was completely inhibited by sodium azide (NaN₃) and potassium cyanide (KCN), suggesting the presence of haem components in its tertiary structure. More interestingly, LiP PR40 illustrated more upper catalytic efficiency and dye-decolorisation aptitude than that of commercial well-known horseradish peroxidase (HRP) from roots of Armoracia rustanica and the purified reported LiP BA45 from Bjerkandera adusta strain CX-9. Consequently, these properties make LiP PR40 a potential candidate for destaining synthetic-dyes and lignin-biodegradation.

摘要

从Zimoula Forest ( Tizi-阿尔及利亚乌祖）。该菌株被鉴定为Phlebia radiata基于内部转录间隔区 (ITS) rDNA 基因测序。过氧化物酶（称为 LiP PR40）经过纯化和表征。基质辅助激光解吸-电离-飞行时间质谱 (MALDI-TOF/MS) 分析表明，LiP PR40 酶是一种分子量为 40,125.31 Da 的单体。LiP PR40 的 25 个 N 端残基序列与真菌 LiP 的序列具有高度相似性。有趣的是，LiP PR40 在 pH 3 和 80 °C 下表现出优异的活性，比活性和 Reinheitzahl (RZ) 水平分别为 510 U/mg 和 2.81。此外，它被叠氮化钠完全抑制（NaN ₃) 和氰化钾 (KCN)，表明其三级结构中存在血红素成分。更有趣的是，LiP PR40 的催化效率和染料脱色能力比商业知名的来自Armoracia rustanica根的辣根过氧化物酶 (HRP) 和来自Bjerkandera adusta菌株 CX-9的纯化报道的 LiP BA45 更高。因此，这些特性使 LiP PR40 成为合成染料脱色和木质素生物降解的潜在候选者。