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Paës G, Navarro D, Benoit Y, Blanquet S, Chabbert B, Chaussepied B, Coutinho PM, Durand S, Grigoriev IV, Haon M, Heux L, Launay C, Margeot A, Nishiyama Y, Raouche S, Rosso MN, Bonnin E, Berrin JG. Tracking of enzymatic biomass deconstruction by fungal secretomes highlights markers of lignocellulose recalcitrance. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:76. [PMID: 30976326 PMCID: PMC6442405 DOI: 10.1186/s13068-019-1417-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 03/23/2019] [Indexed: 05/12/2023]
Abstract
BACKGROUND Lignocellulose biomass is known as a recalcitrant material towards enzymatic hydrolysis, increasing the process cost in biorefinery. In nature, filamentous fungi naturally degrade lignocellulose, using an arsenal of hydrolytic and oxidative enzymes. Assessment of enzyme hydrolysis efficiency generally relies on the yield of glucose for a given biomass. To better understand the markers governing recalcitrance to enzymatic degradation, there is a need to enlarge the set of parameters followed during deconstruction. RESULTS Industrially-pretreated biomass feedstocks from wheat straw, miscanthus and poplar were sequentially hydrolysed following two steps. First, standard secretome from Trichoderma reesei was used to maximize cellulose hydrolysis, producing three recalcitrant lignin-enriched solid substrates. Then fungal secretomes from three basidiomycete saprotrophs (Laetisaria arvalis, Artolenzites elegans and Trametes ljubarskyi) displaying various hydrolytic and oxidative enzymatic profiles were applied to these recalcitrant substrates, and compared to the T. reesei secretome. As a result, most of the glucose was released after the first hydrolysis step. After the second hydrolysis step, half of the remaining glucose amount was released. Overall, glucose yield after the two sequential hydrolyses was more dependent on the biomass source than on the fungal secretomes enzymatic profile. Solid residues obtained after the two hydrolysis steps were characterized using complementary methodologies. Correlation analysis of several physico-chemical parameters showed that released glucose yield was negatively correlated with lignin content and cellulose crystallinity while positively correlated with xylose content and water sorption. Water sorption appears as a pivotal marker of the recalcitrance as it reflects chemical and structural properties of lignocellulosic biomass. CONCLUSIONS Fungal secretomes applied to highly recalcitrant biomass samples can further extend the release of the remaining glucose. The glucose yield can be correlated to chemical and physical markers, which appear to be independent from the biomass type and secretome. Overall, correlations between these markers reveal how nano-scale properties (polymer content and organization) influence macro-scale properties (particle size and water sorption). Further systematic assessment of these markers during enzymatic degradation will foster the development of novel cocktails to unlock the degradation of lignocellulose biomass.
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Affiliation(s)
- Gabriel Paës
- FARE Laboratory, INRA, Université de Reims Champagne-Ardenne, Reims, France
| | - David Navarro
- INRA, Aix Marseille Univ., UMR1163, BBF, Biodiversité et Biotechnologie Fongiques, Marseille, France
- INRA, Aix-Marseille Univ., UMR1163, CIRM-CF, Marseille, France
| | - Yves Benoit
- IFP Energies Nouvelles, Rueil-Malmaison, France
| | | | - Brigitte Chabbert
- FARE Laboratory, INRA, Université de Reims Champagne-Ardenne, Reims, France
| | | | - Pedro M. Coutinho
- CNRS, Aix-Marseille Univ., UMR7857 AFMB, Architecture et Fonction des Macromolécules Biologiques, Marseille, France
| | - Sylvie Durand
- INRA, UR1268 Biopolymères Interactions Assemblages, Nantes, France
| | - Igor V. Grigoriev
- US Department of Energy Joint Genome Institute, Walnut Creek, CA USA
- Department of Plant and Microbial Biology, University of California Berkeley, Berkeley, CA USA
| | - Mireille Haon
- INRA, Aix Marseille Univ., UMR1163, BBF, Biodiversité et Biotechnologie Fongiques, Marseille, France
| | - Laurent Heux
- CNRS, Univ. Grenoble Alpes, CERMAV, Grenoble, France
| | - Charlène Launay
- INRA, UR1268 Biopolymères Interactions Assemblages, Nantes, France
| | | | | | - Sana Raouche
- INRA, Aix Marseille Univ., UMR1163, BBF, Biodiversité et Biotechnologie Fongiques, Marseille, France
| | - Marie-Noëlle Rosso
- INRA, Aix Marseille Univ., UMR1163, BBF, Biodiversité et Biotechnologie Fongiques, Marseille, France
| | - Estelle Bonnin
- INRA, UR1268 Biopolymères Interactions Assemblages, Nantes, France
| | - Jean-Guy Berrin
- INRA, Aix Marseille Univ., UMR1163, BBF, Biodiversité et Biotechnologie Fongiques, Marseille, France
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