Novel redox-active enzymes for ligninolytic applications revealed from multiomics analyses of Peniophora sp. CBMAI 1063, a laccase hyper-producer strain

João Paulo L Franco Cairo,Igor V R Otero,Lívia B Brenelli,Pedro H Mainardi,Fabio M Squina,Thiago Augusto Gonçalves,Lara D Sette,Claus Felby,Marcelo V Liberato,Gabriela F Persinoti

doi:10.1038/s41598-019-53608-1

Abstract

The repertoire of redox-active enzymes produced by the marine fungus Peniophora sp. CBMAI 1063, a laccase hyper-producer strain, was characterized by omics analyses. The genome revealed 309 Carbohydrate-Active Enzymes (CAZymes) genes, including 48 predicted genes related to the modification and degradation of lignin, whith 303 being transcribed under cultivation in optimized saline conditions for laccase production. The secretome confirmed that the fungus can produce a versatile ligninolytic enzyme cocktail. It secretes 56 CAZymes, including 11 oxidative enzymes classified as members of auxiliary activity families (AAs), comprising two laccases, Pnh_Lac1 and Pnh_Lac2, the first is the major secretory protein of the fungi. The Pnh_Lac1-mediator system was able to promote the depolymerization of lignin fragments and polymeric lignin removal from pretreated sugarcane bagasse, confirming viability of this fungus enzymatic system for lignocellulose-based bioproducts applications.

Highlights

Marine-derived fungal species have been considered attractive producers of ligninolytic, hemicellulolytic and other industrial enzymes, presenting different properties compared to terrestrial enzymes, such as high salt tolerance and thermostability[1]
The subfamily AA1_1 has members of the ‘true’ laccases EC 1.10.3.2 or the blue copper oxidases, which are able to oxidize a wide range of aromatic compounds, 1Brazilian Biorenewables National Laboratory (LNBR), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas, Brazil. 2Programa de Processos Tecnológicos e Ambientais, Universidade de Sorocaba (UNISO), Sorocaba, Brazil. 3Universidade Estadual Paulista (UNESP), Instituto de Biociências, Rio Claro, Brazil. 4Departamento de Bioquímica e Biologia Tecidual, Instituto de Biologia, Universidade de Campinas (UNICAMP), Campinas, SP, Brasil. 5University of Copenhagen, Faculty of Science, Department of Geosciences and Natural Resource Management, Frederiksberg C, Denmark. 6These authors contributed : Lívia B
CBMAI 1063 genome content is distinct to other related species

Summary

Introduction

Marine-derived fungal species have been considered attractive producers of ligninolytic, hemicellulolytic and other industrial enzymes, presenting different properties compared to terrestrial enzymes, such as high salt tolerance and thermostability[1]. White-rot fungi simultaneously attack lignin, hemicellulose and cellulose, the main components of the plant cell wall, and their genomes generally have more genes encoding for oxidative enzymes when compared to brown-rot and other groups of basidiomycetes[5,6]. Lignin degradation/modification in white-rot fungi is generally performed via the action of enzymes such as laccases and peroxidases while in brown-rot fungi it is driven by Fenton reactions (Fe2+ + H2O2 → Fe3+ + HO + OH− and Fe3+ + H2O2 → Fe2+ + HOO + H+). Other AA families are reported to potentially drive lignin degradation and modification through Fenton reactions, such as AA3, AA7 and AA8, since the majority of their members can generate H2O2 as a by-product[7,11]. Structural characteristics of the protein and its potential application to promote lignin modification and degradation were explored

Methods

Results

Conclusion