Homologous expression, purification, and characterization of a recombinant acetylxylan esterase from Aspergillus nidulans.
Int J Biol Macromol
; : 135816, 2024 Sep 19.
Article
in En
| MEDLINE
| ID: mdl-39306183
ABSTRACT
Acetylxylan esterases (AXEs) are essential enzymes that break down the acetyl groups in acetylated xylan found in plant cell walls polysaccharides. They work synergistically with backbone-depolymerizing xylanolytic enzymes to accelerate the degradation of complex polysaccharides. In this study, we cloned the gene axeA, which encodes the acetylxylan esterase from Aspergillus nidulans FGSC A4 (AxeAN), into the pEXPYR expression vector and introduced it into the high protein-producing strain A. nidulans A773. The purified AxeAN, with a molecular weight of 33.5â¯kDa as confirmed by SDS-PAGE, was found to be active on ρ-nitrophenyl acetate (ρNPA), exhibiting a remarkably high specific activity (170â¯Uâ¯mg-1) at pHâ¯7.0 and 55⯰C. AxeAN demonstrated stability over a wide pH range (5.5-9.0), retaining >80â¯% of its initial activity after 24â¯h. The KM and Vmax were 0.098â¯mmolâ¯L-1 and 320â¯Uâ¯mg-1, respectively, using ρNPA as a substrate. We also evaluated the synergistic effect of AxeAN with an endo-1,4-ß-xylanase from Malbranchea pulchella (MpXyn10) in the hydrolysis of four different xylans (Birchwood, Beechwood, Oat spelt, and Arabinoxylan) to produce xylooligosaccharides (XOS). The best results were obtained using Birchwood xylan as substrate and MpXyn10-AxeAN as biocatalysts after 24â¯h of reaction (50⯰C), with an XOS-yield of 91â¯%, value 41â¯% higher when compared to MpXyn10 (XOS-yield of 63â¯%). These findings showed the potential of the application of AxeAN, together with other xylanases, to produce xylooligosaccharides with high purity and other products with high added value in the field of lignocellulosic biorefinery.
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01-internacional
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MEDLINE
Language:
En
Journal:
Int J Biol Macromol
Year:
2024
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Article
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