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Current Biotechnology


ISSN (Print): 2211-5501
ISSN (Online): 2211-551X

Research Article

Enhanced Production of β-Xylosidase from Aspergillus Niger ADH-11 and Development of Synergistic Enzyme Cocktail for Saccharification of Sugarcane Bagasse

Author(s): Harshvadan Patel*, Jyoti Divecha and Amita Shah*

Volume 7, Issue 4, 2018

Page: [273 - 287] Pages: 15

DOI: 10.2174/2211550105666151207184921

Price: $65


Background: β-Xylosidase plays a crucial role in xylan hydrolysis and is a necessary component in enzyme cocktails used for bioconversion of lignocellulosic biomass. The enzymatic hydrolysis of lignocellulosic biomass needs a highly balanced composition of cellulases and hemicellulases. Commercial cellulases are often poor in accessory hemicellulolytic enzymes like β-xylosidase. Hence the present investigation was focused on optimization of β-xylosidase production employing low cost technology, characterization of enzyme and its application in enzymatic saccharification of sugarcane bagasse.

Methods: Newly isolated xylanolytic strain Aspergillus niger ADH-11 was exploited for production of β-xylosidase under solid state fermentation. Response surface methodology was used for optimization of β-xylosidase production under solid state fermentation. Physico chemical properties of crude β- xylosidase were evaluated. Crude enzyme was supplemented with commercial cellulases for enzymatic saccharification of mild alkali treated sugar cane bagasse. Reducing sugars from enzymatic hydrolyzate were analyzed using dinitrosalysylic acid (DNS) method and monomeric sugars were analyzed using high performance liquid chromatography (HPLC).

Results: Statistical optimization by response surface methodology increased β-xylosidase production by 2.85 fold and maximum yield after optimization was 214 U/g. In addition to β-xylosidase, the crude enzyme extract was also found to have multiple xylanolytic and cellulolytic enzymes. Crude β- xylosidase was optimally active at temperature 65°C and at pH 4.0. The enzyme was found to be highly stable at its optimum temperature (65°C) up to 3 h and during storage at refrigeration temperature (5- 7°C) for 2 months. Partially purified β-xylosidase showed single activity band in zymogram. Crude β- xylosidase retained 54.52 and 84.00 % activity in the presence of xylose (12 mM) and glucose (200 mM) respectively. The synergistic action of β-xylosidase rich multiple enzymes of crude extract with commercial cellulase increased glucose, xylose and arabinose yield and also reduced cellulase dose.

Conclusion: The present study established that β-xylosidase and accessory hemicellulolytic enzymes of A. niger ADH-11 have significant effect on both cellulose and xylan hydrolysis and can be used to develop a superior enzyme blend with lesser dose of commercial cellulase for saccharification of pretreated sugarcane bagasse.

Keywords: Aspergillus niger ADH-11, β-Xylosidase, response surface methodology, mild alkali treated sugarcane bagasse, synergistic action, cellulose.

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