Limits...
Fast solubilization of recalcitrant cellulosic biomass by the basidiomycete fungus Laetisaria arvalis involves successive secretion of oxidative and hydrolytic enzymes.

Navarro D, Rosso MN, Haon M, Olivé C, Bonnin E, Lesage-Meessen L, Chevret D, Coutinho PM, Henrissat B, Berrin JG - Biotechnol Biofuels (2014)

Bottom Line: Temporal analyses of secretomes indicated that the unusual degradation efficiency of L. arvalis relies on its early response to the carbon source, and on the finely tuned sequential secretion of several lytic polysaccharide monooxygenases and hydrolytic enzymes targeting cellulose.The cellulolytic capabilities of this basidiomycete fungus result from the rapid, selective and successive secretion of oxidative and hydrolytic enzymes.These enzymes expressed at critical times during biomass degradation may inspire the design of improved enzyme cocktails for the conversion of plant cell wall resources into fermentable sugars.

View Article: PubMed Central - PubMed

Affiliation: INRA, UMR1163 Biotechnologie des Champignons Filamenteux, 13288 Marseille, France ; Aix-Marseille Université, Polytech Marseille, UMR1163 Biotechnologie des Champignons Filamenteux, 13288 Marseille, France ; CIRM-CF, UMR1163 Biotechnologie des Champignons Filamenteux, 13288 Marseille, France.

ABSTRACT

Background: Enzymatic breakdown of lignocellulosic biomass is a known bottleneck for the production of high-value molecules and biofuels from renewable sources. Filamentous fungi are the predominant natural source of enzymes acting on lignocellulose. We describe the extraordinary cellulose-deconstructing capacity of the basidiomycete Laetisaria arvalis, a soil-inhabiting fungus.

Results: The L. arvalis strain displayed the capacity to grow on wheat straw as the sole carbon source and to fully digest cellulose filter paper. The cellulolytic activity exhibited in the secretomes of L. arvalis was up to 7.5 times higher than that of a reference Trichoderma reesei industrial strain, resulting in a significant improvement of the glucose release from steam-exploded wheat straw. Global transcriptome and secretome analyses revealed that L. arvalis produces a unique repertoire of carbohydrate-active enzymes in the fungal taxa, including a complete set of enzymes acting on cellulose. Temporal analyses of secretomes indicated that the unusual degradation efficiency of L. arvalis relies on its early response to the carbon source, and on the finely tuned sequential secretion of several lytic polysaccharide monooxygenases and hydrolytic enzymes targeting cellulose.

Conclusions: The present study illustrates the adaptation of a litter-rot fungus to the rapid breakdown of recalcitrant plant biomass. The cellulolytic capabilities of this basidiomycete fungus result from the rapid, selective and successive secretion of oxidative and hydrolytic enzymes. These enzymes expressed at critical times during biomass degradation may inspire the design of improved enzyme cocktails for the conversion of plant cell wall resources into fermentable sugars.

No MeSH data available.


Related in: MedlinePlus

Evaluation of the cellulose-degrading capabilities ofLaetisaria arvalis. Growth was performed in minimal medium containing filter paper strips as the sole carbon source. Pictures were taken after one day (A), five days (B) and 10 days (C). Left tube: control without inoculum; middle tube: L. arvalis; right tube: Trichoderma reesei QM6a. These results are representative of several independent experiments.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC4197297&req=5

Fig2: Evaluation of the cellulose-degrading capabilities ofLaetisaria arvalis. Growth was performed in minimal medium containing filter paper strips as the sole carbon source. Pictures were taken after one day (A), five days (B) and 10 days (C). Left tube: control without inoculum; middle tube: L. arvalis; right tube: Trichoderma reesei QM6a. These results are representative of several independent experiments.

Mentions: The L. arvalis strain CIRM-BRFM514 was identified when screening fungal strains for their capacity to efficiently degrade lignocellulosic biomass [12,13]. This strain displayed a great capacity to grow on wheat straw (WS) and on the leftover WS residue (WS-R) resulting from steam explosion under acidic conditions and subsequent saccharification (enzymatic conversion into sugars) with a T. reesei enzyme cocktail. The difference between WS and WS-R in terms of sugar composition is described in Additional file 1: Table S1. Indeed, the mycelium of L. arvalis fully colonized Petri dishes after only four days growth on WS and WS-R as the sole carbon source (Figure 1). L. arvalis was also able to grow and fully digest filter paper strips soaked in minimal medium within 10 days (Figure 2). In the same conditions, the wild-type T. reesei strain QM6a grew without visible breakdown of cellulose (Figure 2).Figure 1


Fast solubilization of recalcitrant cellulosic biomass by the basidiomycete fungus Laetisaria arvalis involves successive secretion of oxidative and hydrolytic enzymes.

Navarro D, Rosso MN, Haon M, Olivé C, Bonnin E, Lesage-Meessen L, Chevret D, Coutinho PM, Henrissat B, Berrin JG - Biotechnol Biofuels (2014)

Evaluation of the cellulose-degrading capabilities ofLaetisaria arvalis. Growth was performed in minimal medium containing filter paper strips as the sole carbon source. Pictures were taken after one day (A), five days (B) and 10 days (C). Left tube: control without inoculum; middle tube: L. arvalis; right tube: Trichoderma reesei QM6a. These results are representative of several independent experiments.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4197297&req=5

Fig2: Evaluation of the cellulose-degrading capabilities ofLaetisaria arvalis. Growth was performed in minimal medium containing filter paper strips as the sole carbon source. Pictures were taken after one day (A), five days (B) and 10 days (C). Left tube: control without inoculum; middle tube: L. arvalis; right tube: Trichoderma reesei QM6a. These results are representative of several independent experiments.
Mentions: The L. arvalis strain CIRM-BRFM514 was identified when screening fungal strains for their capacity to efficiently degrade lignocellulosic biomass [12,13]. This strain displayed a great capacity to grow on wheat straw (WS) and on the leftover WS residue (WS-R) resulting from steam explosion under acidic conditions and subsequent saccharification (enzymatic conversion into sugars) with a T. reesei enzyme cocktail. The difference between WS and WS-R in terms of sugar composition is described in Additional file 1: Table S1. Indeed, the mycelium of L. arvalis fully colonized Petri dishes after only four days growth on WS and WS-R as the sole carbon source (Figure 1). L. arvalis was also able to grow and fully digest filter paper strips soaked in minimal medium within 10 days (Figure 2). In the same conditions, the wild-type T. reesei strain QM6a grew without visible breakdown of cellulose (Figure 2).Figure 1

Bottom Line: Temporal analyses of secretomes indicated that the unusual degradation efficiency of L. arvalis relies on its early response to the carbon source, and on the finely tuned sequential secretion of several lytic polysaccharide monooxygenases and hydrolytic enzymes targeting cellulose.The cellulolytic capabilities of this basidiomycete fungus result from the rapid, selective and successive secretion of oxidative and hydrolytic enzymes.These enzymes expressed at critical times during biomass degradation may inspire the design of improved enzyme cocktails for the conversion of plant cell wall resources into fermentable sugars.

View Article: PubMed Central - PubMed

Affiliation: INRA, UMR1163 Biotechnologie des Champignons Filamenteux, 13288 Marseille, France ; Aix-Marseille Université, Polytech Marseille, UMR1163 Biotechnologie des Champignons Filamenteux, 13288 Marseille, France ; CIRM-CF, UMR1163 Biotechnologie des Champignons Filamenteux, 13288 Marseille, France.

ABSTRACT

Background: Enzymatic breakdown of lignocellulosic biomass is a known bottleneck for the production of high-value molecules and biofuels from renewable sources. Filamentous fungi are the predominant natural source of enzymes acting on lignocellulose. We describe the extraordinary cellulose-deconstructing capacity of the basidiomycete Laetisaria arvalis, a soil-inhabiting fungus.

Results: The L. arvalis strain displayed the capacity to grow on wheat straw as the sole carbon source and to fully digest cellulose filter paper. The cellulolytic activity exhibited in the secretomes of L. arvalis was up to 7.5 times higher than that of a reference Trichoderma reesei industrial strain, resulting in a significant improvement of the glucose release from steam-exploded wheat straw. Global transcriptome and secretome analyses revealed that L. arvalis produces a unique repertoire of carbohydrate-active enzymes in the fungal taxa, including a complete set of enzymes acting on cellulose. Temporal analyses of secretomes indicated that the unusual degradation efficiency of L. arvalis relies on its early response to the carbon source, and on the finely tuned sequential secretion of several lytic polysaccharide monooxygenases and hydrolytic enzymes targeting cellulose.

Conclusions: The present study illustrates the adaptation of a litter-rot fungus to the rapid breakdown of recalcitrant plant biomass. The cellulolytic capabilities of this basidiomycete fungus result from the rapid, selective and successive secretion of oxidative and hydrolytic enzymes. These enzymes expressed at critical times during biomass degradation may inspire the design of improved enzyme cocktails for the conversion of plant cell wall resources into fermentable sugars.

No MeSH data available.


Related in: MedlinePlus