Relationships between extracellular laccase production and discoloring of textile dyes by white-rot basidiomycete fungi

2015 ◽  
Vol 208 ◽  
pp. S60-S61
Author(s):  
Gabriela Popa ◽  
Calina Petruta Cornea
2020 ◽  
Vol 6 (4) ◽  
pp. 340
Author(s):  
Olga A. Glazunova ◽  
Konstantin V. Moiseenko ◽  
Olga S. Savinova ◽  
Tatyana V. Fedorova

Although, currently, more than 100 laccases have been purified from basidiomycete fungi, the majority of these laccases were obtained from fungi of the Polyporales order, and only scarce data are available about the laccases from other fungi. In this article, laccase production by the white-rot basidiomycete fungus Peniophora lycii, belonging to the Russulales order, was investigated. It was shown that, under copper induction, this fungus secreted three different laccase isozymes. Two laccase isozymes—Lac5 and LacA—were purified and their corresponding nucleotide sequences were determined. Both purified laccases were relatively thermostable with periods of half-life at 70 °C of 10 and 8 min for Lac5 and LacA, respectively. The laccases demonstrated the highest activity toward ABTS (97 U·mg−1 for Lac5 and 121 U·mg−1 for LacA at pH 4.5); Lac5 demonstrated the lowest activity toward 2,6-DMP (2.5 U·mg−1 at pH 4.5), while LacA demonstrated this towards gallic acid (1.4 U·mg−1 at pH 4.5). Both Lac5 and LacA were able to efficiently decolorize such dyes as RBBR and Bromcresol Green. Additionally, phylogenetic relationships among laccases of Peniophora spp. were reconstructed, and groups of orthologous genes were determined. Based on these groups, all currently available data about laccases of Peniophora spp. were systematized.


2021 ◽  
Vol 22 (3) ◽  
pp. 1157
Author(s):  
Pablo Aza ◽  
Felipe de Salas ◽  
Gonzalo Molpeceres ◽  
David Rodríguez-Escribano ◽  
Iñigo de la Fuente ◽  
...  

Laccases secreted by saprotrophic basidiomycete fungi are versatile biocatalysts able to oxidize a wide range of aromatic compounds using oxygen as the sole requirement. Saccharomyces cerevisiae is a preferred host for engineering fungal laccases. To assist the difficult secretion of active enzymes by yeast, the native signal peptide is usually replaced by the preproleader of S. cerevisiae alfa mating factor (MFα1). However, in most cases, only basal enzyme levels are obtained. During directed evolution in S. cerevisiae of laccases fused to the α-factor preproleader, we demonstrated that mutations accumulated in the signal peptide notably raised enzyme secretion. Here we describe different protein engineering approaches carried out to enhance the laccase activity detected in the liquid extracts of S. cerevisiae cultures. We demonstrate the improved secretion of native and engineered laccases by using the fittest mutated α-factor preproleader obtained through successive laccase evolution campaigns in our lab. Special attention is also paid to the role of protein N-glycosylation in laccase production and properties, and to the introduction of conserved amino acids through consensus design enabling the expression of certain laccases otherwise not produced by the yeast. Finally, we revise the contribution of mutations accumulated in laccase coding sequence (CDS) during previous directed evolution campaigns that facilitate enzyme production.


Author(s):  
Johann Hess ◽  
Christian Leitner ◽  
Christiane Galhaup ◽  
Klaus D. Kulbe ◽  
Barbara Hinterstoisser ◽  
...  

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