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A new thermophilic Parageobacillus sp. DSM 35475 produces a thermostable hemicellulolytic secretome from spent mushroom substrate and digestate

delete2026-08-03
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OA
AI
L
Luca Bombardi
V
Valerio Sabellico
L
Luca Zuliani
G
Giovanni Gallo
D
David Cannella
M
Martina Aulitto *
S
Salvatore Fusco *
DOI:10.1016/j.ijbiomac.2026.153852delete
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Abstract

Abstract

En 中文
The development of robust enzyme systems and the use of low-cost feedstocks for lignocellulosic biomass deconstruction remain major challenges for biorefineries. Here, we report a strategy to discover and produce thermostable hemicellulolytic enzymes from industrial microbiomes enriched on spent mushroom substrate (SMS) at 70 °C. A thermophilic bacterium representing a novel species, Parageobacillus sp. DSM 35475, was isolated and cultivated on a medium composed exclusively of SMS and digestate, demonstrating the feasibility of producing extracellular enzymes from agro-industrial residues. The resulting cell-free secretome exhibited xylanase activity of 0.22 U/mL, with an optimum at 80 °C and pH 7, while retaining more than 30% of its maximal activity between 60 and 90 °C and more than 50% activity after prolonged incubation at 75–80 °C. More than 40% of the initial activity was preserved after 80 days of storage at 4 °C. HPAEC-PAD analysis of hydrolysis products, together with zymographic and genomic analyses, indicated the presence of a multifunctional hemicellulolytic system comprising endo-xylanase, β-xylosidase, α-L-arabinofuranosidase, and endo-mannanase activities. The secretome hydrolysed beechwood xylan, arabinoxylan and alkali-pretreated SMS, releasing mixtures of mono- and oligosaccharides under thermophilic conditions. Genome annotation predicted a diverse CAZyme repertoire and a dedicated xylan/arabinan utilisation locus consistent with the observed biochemical phenotype. Overall, this study demonstrates the feasibility of producing a thermostable hemicellulolytic secretome from low-cost agro-industrial residues and identifies Parageobacillus sp. DSM 35475 as a promising source of thermophilic enzymes for future lignocellulose bioconversion.
Keywords:
Lignocellulosic biomass
Xylanase
Industrial microbiomes
Biorefinery
Waste valorisation
Thermophiles

Journal

International Journal of Biological Macromolecules cover
International Journal of Biological Macromolecules
IF:
8.5
Papers:
4.9W
Citations:
21.7W

Organization

U
universite libre de bruxelles
Scholars:
1.9W
Papers: 1.6W
Citations: 27
U
University of Naples Federico II
Scholars:
4.6W
Papers: 3.6W
Citations: 51
U
university of verona
Scholars:
2.2K
Papers: 887
Citations: 0
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