Lytic xylan oxidases from wood-decay fungi unlock biomass degradation

Wood biomass is the most abundant feedstock envisioned for the development of modern biorefineries. However, the cost-ef-fective conversion of this form of biomass into commodity products is limited by its resistance to enzymatic degradation. Here we describe a new family of fungal lytic polysaccharide monooxygenases (LPMOs) prevalent among white-rot and brown-rot basidiomycetes that is active on xylans—a recalcitrant polysaccharide abundant in wood biomass. Two AA14 LPMO members from the white-rot fungus Pycnoporus coccineus substantially increase the efficiency of wood saccharification through oxida-tive cleavage of highly refractory xylan-coated cellulose fibers. The discovery of this unique enzyme activity advances our knowledge on the degradation of woody biomass in nature and offers an innovative solution for improving enzyme cocktails for biorefinery applications

Improvement of anaerobic degradation by white-rot fungi pretreatment of lignocellulosic biomass : A review

International audienceAnaerobic digestion of lignocellulosic biomass appears to be an efficient process for the production of energy whilst answering present-day environmental challenges. However, lignin contained in lignocellulosic biomass is hardly biodegradable, thus representing a major obstacle for maximum methane production. Consequently, although pretreatments need to be considered, their cost is a limit for their full-scale use. Biological pretreatments are a cheaper alternative in this context. Several biological pre-treatments have been studied for anaerobic digestion: ensiling, partial composting, specific microbial consortia, enzymes and fungi. Simple, inexpensive and efficient pretreatments can be obtained using fungi. White-rot fungi (WRF), have been considered as most capable of delignifying a substrate. However, their use in the pretreatment of substrates for anaerobic digestion is quite recent and still needs to be investigated. This review compares fungal pretreatment with other biological treatments for anaerobic digestion of lignocellulosic biomass. Enzymatic mechanisms for WRF pretreatments are then exposed. The literature data regarding the improvement of anaerobic digestibility with WRF pretreatment are summarized (anaerobic digestion and in vitro digestibility with rumen microorganisms). Finally, lignocellulosic biomass features allowing the improvement of anaerobic digestion are exposed (porosity, cellulose crystallinity, etc.). The possible effects of WRF on these characteristics are discussed and industrial perspectives for WRF pretreatments are presented. (C) 2016 Elsevier Ltd. All rights reserved

Purification, crystallisation and X-ray diffraction study of fully functional laccases from two ligninolytic fungi

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Purification, crystallisation and X-ray diffraction study of fully functional laccases from two ligninolytic fungi

International audienc

Development of formal and molecular genetic methods to produce laccase in filamentous fungi

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Differential Regulation of the Cellulase Transcription Factors XYR1, ACE2, and ACE1 in Trichoderma reesei Strains Producing High and Low Levels of Cellulase ▿ †

Due to its capacity to produce large amounts of cellulases, Trichoderma reesei is increasingly being investigated for second-generation biofuel production from lignocellulosic biomass. The induction mechanisms of T. reesei cellulases have been described recently, but the regulation of the genes involved in their transcription has not been studied thoroughly. Here we report the regulation of expression of the two activator genes xyr1 and ace2, and the corepressor gene ace1, during the induction of cellulase biosynthesis by the inducer lactose in T. reesei QM 9414, a strain producing low levels of cellulase (low producer). We show that all three genes are induced by lactose. xyr1 was also induced by d-galactose, but this induction was independent of d-galactose metabolism. Moreover, ace1 was carbon catabolite repressed, whereas full induction of xyr1 and ace2 in fact required CRE1. Significant differences in these regulatory patterns were observed in the high-producer strain RUT C30 and the hyperproducer strain T. reesei CL847. These observations suggest that a strongly elevated basal transcription level of xyr1 and reduced upregulation of ace1 by lactose may have been important for generating the hyperproducer strain and that thus, these genes are major control elements of cellulase production