White-rot basidiomycetes Junghuhnia nitida and Steccherinum bourdotii: Oxidative potential and laccase properties in comparison with Trametes hirsuta and Coriolopsis caperata

Abstract

White-rot basidiomycetes from the poorly studied residual polyporoid clade of Polyporales order Junghuhnia nitida (Pers.) Ryvarden and Steccherinum bourdotii Saliba & A. David grow as secondary xylotrohps on well decomposed woody materials. The main objective of the current study was to compare oxidative potential, growth, production of oxidative enzymes and laccase properties of J. nitida and S. bourdotii with that of typical primary xylotrohps Trametes hirsuta (Wulfen) Lloyd and Coriolopsis caperata (Berk.) Murrill, belonging to the core polyporoid clade. For the first time we report species J. nitida and S. bourdotii as active laccase producers. New laccases from J. nitida and S. bourdotii were purified and characterized. They had an identical molecular weight of 63 kDa and isoelectric points of 3.4 and 3.1, respectively. However, the redox potential of the T1 copper site for both J. nitida (610 mV) and S. bourdotii (640 mV) laccases was lower than those for T. hirsuta and C. caperata laccases. The new laccases showed higher temperature optima and better thermal stability than T. hirsuta and C. caperata laccases. Their half-lives were more than 40 min at 70 °C. The laccases from J. nitida and S. bourdotii showed higher affinity to syringyl-type phenolic compounds than T. hirsuta and C. caperata laccases. The oxidative potential of studied fungi as well as the properties of their laccases are discussed in terms of the fungal life-style.

Evolutionary Relationships Between the Laccase Genes of Polyporales: Orthology-Based Classification of Laccase Isozymes and Functional Insight From Trametes hirsuta

“…Among the substrates investigated, all isozymes showed the lowest affinity toward guaiacol and catechol (the highest K M values) and the highest affinity toward synapic acid. It is interesting that for the minor rLacD , the affinities toward 2,6-DMP and synapic acid (S-type substrates) were slightly higher than for the major LacA isozyme, which is a characteristic feature of the Steccherinaceae group laccases (Glazunova et al, 2018a). It also should be noted that among the minor laccases ( rLacC, rLacF, and rLacD ), both S-type substrates were better for rLacD and rLacF , while rLacC affinity toward 2,6-DMP was significantly poorer than it was toward synapic acid.…”

Laccases with Variable Properties from Different Strains of Steccherinum ochraceum: Does Glycosylation Matter?

“…Laccase purification and characterization (including determination of molecular weight; p I ; thermostability, τ 1/2 ; melting point, T max ; and enthalpy of denaturation, Δ H cal ) procedures were identical to those described in [22]. Laccase activity was measured spectrophotometrically with pyrocatechol as a substrate (ε 410 = 740 cm −1 ·M −1 ).…”

“…Steccherinum is a genus of basidiomycete fungi belonging to the Steccherinaceae family (order Polyporales). Some members of this family— Antrodiella faginea , Junghuhnia nitida , Steccherinum murashkinskyi , Steccherinum ochraceum and Steccherinum bourdotii –were previously reported as fungi with high laccase-producing capability [22,23,24]. Besides being very thermostable, laccases from these fungi have high catalytic efficiency towards different phenolic substrates (especially of syringyl-type) and dyes [22,25,26].…”

Fungal Adaptation to the Advanced Stages of Wood Decomposition: Insights from the Steccherinum ochraceum

“…After morphological and genetic verifications, the strain was deposited in the Komarov Botanical Institute Basidiomycetes Culture Collection (LE-BIN; St. Petersburg, Russia) as S. ochraceum LE-BIN 3174. The sequence of its ITS1-5.8S rRNA-ITS2 region was obtained as described in [22] and deposited into the NCBI GenBank (Table S1).…”

“…Being widely distributed in forest ecosystems throughout the world, these fungi are of broad ecological interest [20,21]. Moreover, some members of this family were previously reported as fungi with high biotechnological potential [22,23,24,25,26]. Steccherinum ochraceum is a typical representative of the Steccherinaceae family.…”