Characterization of a novel Lytic Polysaccharide Monooxygenase from Malbranchea cinnamomea exhibiting dual catalytic behavior

Basotra, Neha; Dhiman, Saurabh Sudha; Agrawal, Dhruv; Sani, Rajesh K.; Tsang, Adrian; Chadha, Bhupinder Singh

doi:10.1016/j.carres.2019.04.006

Cited by 39 publications

(14 citation statements)

References 44 publications

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“…One study described how AA9A from Lentinus similis ( Ls AA9A) displayed activity toward xylooligosaccharides, although it was at two magnitudes lower than activity on cellooligosaccharides (20). A very recent study showed that an M. cinnamomea AA9 (PMO9A_MALCI, or Mc AA9G) acted on both cellulose and hemicelluloses equally well, but the available data do not allow an assessment of substrate preferences and background activities in the absence of ascorbic acid were very high in this study (22). One other AA9 that showed weak oxidative activity on xylan when the xylan was combined with cellulose still primarily generated cellooligosaccharides (LPMO9A from Myceliophthora thermophila C 1 [21]).…”

Section: Discussionmentioning

confidence: 60%

“…Importantly, Couturier et al recently described the first two AA14 LPMOs, which seem to target xylan only, likely acting on junction zones of xylan and cellulose (19). Xylan activity has also been described for only three members of the large AA9 family, but in all cases activity on xylan was weak and much lower than the activity on cellulose (20–22). Many questions remain concerning xylan-active LPMOs, such as the structural determinants of their activity on xylan, their physiological relevance, how widespread they are in microorganisms, and the role substrate conformation plays in enzymatic activity.…”

Section: Introductionmentioning

confidence: 94%

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Specific Xylan Activity Revealed for AA9 Lytic Polysaccharide Monooxygenases of the Thermophilic Fungus Malbranchea cinnamomea by Functional Characterization

Hüttner

Várnai

Petrović

et al. 2019

Appl Environ Microbiol

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The Malbranchea cinnamomea LPMOs (McAA9s) showed activity on a broad range of soluble and insoluble substrates, suggesting their involvement in various steps of biomass degradation besides cellulose decomposition. Our results indicate that the fungal AA9 family is more diverse than originally thought and able to degrade almost any kind of plant cell wall polysaccharide. The discovery of an AA9 that preferentially cleaves xylan enhances our understanding of the physiological roles of LPMOs and enables the use of xylan-specific LPMOs in future applications.

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Section: Discussionmentioning

confidence: 60%

Section: Introductionmentioning

confidence: 94%

Specific Xylan Activity Revealed for AA9 Lytic Polysaccharide Monooxygenases of the Thermophilic Fungus Malbranchea cinnamomea by Functional Characterization

Hüttner

Várnai

Petrović

et al. 2019

Appl Environ Microbiol

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“…The LPMO structure from Thermoascus aurantiacus (TaAA9A) (20) revealed a Cu-bound His-brace on a flat extended surface near a conserved Tyr, in the C-terminal loop (LC), putatively involved in substrate binding. AA9 LPMOs were initially assumed to specifically target crystalline regions of polysaccharides but later, activity was also demonstrated on a range of hemicellulose polysaccharides such as xyloglucan (XG), xylan, glucomannan (GM) and mixed-linkage β-glucans (MLG) and also on oligosaccharides (17,(24)(25)(26)(27)(28)(29)(30)(31). The AA9 LPMO from Neurospora crassa (NcAA9C) is active on both cello-oligosaccharides and hemicellulosic substrates suggesting that the enzyme recognizes small stretches of β-1,4-linked glucosyl units (24,25).…”

Section: Introductionmentioning

confidence: 99%

Identification of the molecular determinants driving the substrate specificity of fungal lytic polysaccharide monooxygenases (LPMOs)

Frandsen

Haon

Grisel

et al. 2021

Journal of Biological Chemistry

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Understanding enzymatic breakdown of plant biomass is crucial to develop nature-inspired biotechnological processes. Lytic polysaccharide monooxygenases (LPMOs) are microbial enzymes secreted by fungal saprotrophs involved in carbon recycling. LPMOs modify biomass by oxidatively cleaving polysaccharides thereby enhancing the efficiency of glycoside hydrolases. Fungal AA9 LPMOs are active on cellulose but some members also display activity on hemicelluloses and/or oligosaccharides. Although the active site subsites are well defined for a few model LPMOs, the molecular determinants driving broad substrate specificity are still not easily predictable. Based on bioinformatic clustering and sequence alignments, we selected seven fungal AA9 LPMOs that differ in the amino-acid residues constituting their subsites. Investigation of their substrate specificities revealed that all these LPMOs are active on cellulose and cello-oligosaccharides, as well as plant cell wall-derived hemicellulosic polysaccharides and carry out C4 oxidative cleavage. The product profiles from cello-oligosaccharides degradation suggests that the subtle differences in amino acids sequence within the substrate-binding loop regions lead to different preferred binding modes. Our functional analyses allowed us to probe the molecular determinants of substrate binding within two AA9 LPMO sub-clusters. Many wood-degrading fungal species rich in AA9 genes have at least one AA9 enzyme with structural loop features that allow recognition of short β-(1,4)-linked glucan chains. Time-course monitoring of these AA9 LPMOs on cello-oligosaccharides also provides a useful model system for mechanistic studies of LPMO catalysis. These results are valuable for the understanding of LPMO contribution to wood decaying process in nature and for the development of sustainable biorefineries.

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“…However, only a few attempts have been made to examine their hydrolysis performance on lignocellulosic biomass. Partial replacement of the commercial cellulase cocktail Cellic CTec2 with xylanases or LPMOs from M. cinnamomea resulted in improvement in the hydrolysis of alkali pretreated rice straw [ 16 , 18 ]. A promoting effect on the hydrolysis of alkali pretreated biomass was also observed when secretome fractions of M. cinnamomea were supplemented to Cellic CTec2 [ 19 ].…”

Section: Introductionmentioning

confidence: 99%

Improving the fermentable sugar yields of wheat straw by high-temperature pre-hydrolysis with thermophilic enzymes of Malbranchea cinnamomea

et al. 2020

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Background Enzymatic hydrolysis is a key step in the conversion of lignocellulosic polysaccharides to fermentable sugars for the production of biofuels and high-value chemicals. However, current enzyme preparations from mesophilic fungi are deficient in their thermostability and biomass-hydrolyzing efficiency at high temperatures. Thermophilic fungi represent promising sources of thermostable and highly active enzymes for improving the biomass-to-sugar conversion process. Here we present a comprehensive study on the lignocellulosic biomass-degrading ability and enzyme system of thermophilic fungus Malbranchea cinnamomea N12 and the application of its enzymes in the synergistic hydrolysis of lignocellulosic biomass. Results Malbranchea cinnamomea N12 was capable of utilizing untreated wheat straw to produce high levels of xylanases and efficiently degrading lignocellulose under thermophilic conditions. Temporal analysis of the wheat straw-induced secretome revealed that M. cinnamomea N12 successively degraded the lignocellulosic polysaccharides through sequential secretion of enzymes targeting xylan and cellulose. Xylanase-enriched cocktail from M. cinnamomea N12 was more active on native and alkali‑pretreated wheat straw than the commercial xylanases from Trichoderma reesei over temperatures ranging from 40 to 75 °C. Integration of M. cinnamomea N12 enzymes with the commercial cellulase preparation increased the glucose and xylose yields of alkali‑pretreated wheat straw by 32 and 166%, respectively, with pronounced effects at elevated temperature. Conclusions This study demonstrated the remarkable xylanase-producing ability and strategy of sequential lignocellulose breakdown of M. cinnamomea N12. A new process for the hydrolysis of lignocellulosic biomass was proposed, comprising thermophilic enzymolysis by enzymes of M. cinnamomea N12 followed with mesophilic enzymolysis by commercial cellulases. Developing M. cinnamomea N12 as platforms for thermophilic enzyme mixture production will provide new perspectives for improved conversion yields for current biomass saccharification schemes.

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Characterization of a novel Lytic Polysaccharide Monooxygenase from Malbranchea cinnamomea exhibiting dual catalytic behavior

Cited by 39 publications

References 44 publications

Specific Xylan Activity Revealed for AA9 Lytic Polysaccharide Monooxygenases of the Thermophilic Fungus Malbranchea cinnamomea by Functional Characterization

Specific Xylan Activity Revealed for AA9 Lytic Polysaccharide Monooxygenases of the Thermophilic Fungus Malbranchea cinnamomea by Functional Characterization

Identification of the molecular determinants driving the substrate specificity of fungal lytic polysaccharide monooxygenases (LPMOs)

Improving the fermentable sugar yields of wheat straw by high-temperature pre-hydrolysis with thermophilic enzymes of Malbranchea cinnamomea

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