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<p>β-glucosidase from <i>Humicola brevis</i> var. <i>thermoidea</i> (BglHb) was purified and biochemically characterized. The enzyme was purified 418.1-fold with 4.2% yield; the apparent molecular mass, determined by SDS-PAGE was 125&#xa0;kDa. Optimal pH and temperature were 5.5 and 65&#xa0;°C, and completely stable over the pH range of 5.0 to 8.0. The enzyme retained about 85% of its initial activity after 8&#xa0;h of incubation at 55&#xa0;°C, with t<sub>1/2</sub>=27&#xa0;h. Enzyme incubation at 60 and 65&#xa0;°C resulted in t<sub>1/2</sub> of 0.3 and 1.5&#xa0;h, respectively. Kinetic parameters for the hydrolysis of <i>p</i>NPGlc were <i>V</i><sub>max</sub>=715.3 ± 58.9 U mg<sup>− 1</sup> and <i>K</i><sub>m</sub>=69.9 ± 4.6 µmol L<sup>− 1</sup>. Increasing xylose concentrations up to 200 mmol L<sup>− 1</sup> increased enzyme activity 1.53-fold, reaching a <i>V</i><sub>max</sub> of 1,098.4 ± 75.8 U mg<sup>− 1</sup>, with a <i>K</i><sub>m</sub> of 1.7 ± 0.1 mmol L<sup>− 1</sup>. Ethanol increased relative activity up to 30% in the presence of 10% (v/v) ethanol, and xylose stimulated activity by 53% at 50 mmol L<sup>− 1</sup>, suggesting potential compatibility with bioethanol process streams. The high thermal and pH stability of BglHb, combined with its stimulation by xylose and ethanol, suggests great potential for application in lignocellulosic biomass saccharification.&#xa0;</p> Graphical abstract <p></p>

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Xylose and ethanol stimulate a thermostable β-glucosidase from Humicola brevis var. thermoidea

  • 期刊论文

  • 发表日期：

    2026年1月19日

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  • Luciane Gomes Freire,
  • Aline Pereira de Almeida,
  • Felipe Araújo Nascimento,
  • Camila Langer Marciano,
  • Fabiana Fonseca Zanoelo,
  • Giovana Cristina Giannesi,
  • José Carlos Santos dos Salgado,
  • Maria de Lourdes Teixeira Moraes Polizeli,
  • Roberto Ruller,
  • Douglas Chodi Masui

摘要

β-glucosidase from Humicola brevis var. thermoidea (BglHb) was purified and biochemically characterized. The enzyme was purified 418.1-fold with 4.2% yield; the apparent molecular mass, determined by SDS-PAGE was 125 kDa. Optimal pH and temperature were 5.5 and 65 °C, and completely stable over the pH range of 5.0 to 8.0. The enzyme retained about 85% of its initial activity after 8 h of incubation at 55 °C, with t1/2=27 h. Enzyme incubation at 60 and 65 °C resulted in t1/2 of 0.3 and 1.5 h, respectively. Kinetic parameters for the hydrolysis of pNPGlc were Vmax=715.3 ± 58.9 U mg− 1 and Km=69.9 ± 4.6 µmol L− 1. Increasing xylose concentrations up to 200 mmol L− 1 increased enzyme activity 1.53-fold, reaching a Vmax of 1,098.4 ± 75.8 U mg− 1, with a Km of 1.7 ± 0.1 mmol L− 1. Ethanol increased relative activity up to 30% in the presence of 10% (v/v) ethanol, and xylose stimulated activity by 53% at 50 mmol L− 1, suggesting potential compatibility with bioethanol process streams. The high thermal and pH stability of BglHb, combined with its stimulation by xylose and ethanol, suggests great potential for application in lignocellulosic biomass saccharification. 

Graphical abstract