Isolation, Kinetic Modeling, and Structural Properties of Thermophilic Xylanolytic Complexes Sourced from Agricultural Silage Soils

International Journal of Chemistry | Vol. 14, No. 2, February 2023 | pp. 9–16

DOI: 10.46882/2023/IJC/000172

Article Type: Original Research Paper

Title: Isolation, Kinetic Modeling, and Structural Properties of Thermophilic Xylanolytic Complexes Sourced from Agricultural Silage Soils

Names of Authors: C. N. Nwosu¹, T. H. Sato²*

Authors’ Affiliations:
¹Department of Biochemistry, Nnamdi Azikiwe University, Awka, Nigeria.
²Department of Biomolecular Engineering, Tokyo Institute of Technology, Tokyo, Japan.

Abstract: The industrial hydrolysis of plant biomass into fermentable sugars requires robust xylanolytic enzymes that can resist thermal denaturation during high-temperature operations. This study details the isolation, microstructural profiling, and kinetic optimization of high-yielding endo-xylanase complexes produced by a thermophilic fungal strain sourced from agricultural compost and silage dumpsites. Enrichment culturing was executed in xylan-infused Mandels' media at 50°C, isolating a dominant strain identified via internal transcribed spacer (ITS) rRNA gene sequencing as Aspergillus tubingensis strain SIL-X2. Response surface methodology optimized solid-state fermentation yields using wheat bran matrices. Maximum xylanase activity (48.5 U/mL) was achieved at an incubation temperature of 50°C, an initial substrate pH of 6.5, and a fermentation period of 96 hours. Biochemical characterization showed that the crude enzyme complex retained over 85% of its initial catalytic activity across a temperature range of 45 to 65°C and a pH stability window of 5.5 to 7.5 for 24 hours. The high thermal stability of this enzyme system, along with its independence from calcium ions, makes it a viable candidate for bio-refinery industrial operations.

Keywords: Xylanase; Aspergillus tubingensis; Solid-state fermentation; Thermal stability; Kinetic optimization; Biomass conversion

Manuscript Timeline: Received: November 10, 2022; Revised: December 18, 2022; Accepted: January 14, 2023; Published: February 06, 2023.

Citation: Nwosu, C. N., & Sato, T. H. (2023). Isolation, Kinetic Modeling, and Structural Properties of Thermophilic Xylanolytic Complexes Sourced from Agricultural Silage Soils. International Journal of Chemistry, 14(2), 9–16.

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