Isolation, Structural Profiling, and Optimizing Kinetics of Cellulolytic Complexes Sourced from Thermophilic Aspergillus Strains

International Journal of Chemistry | Vol. 10, No. 11, November 2019 | pp. 81–88

DOI: 10.46882/2019/IJC/000133

Article Type: Original Research Paper

Title: Isolation, Structural Profiling, and Optimizing Kinetics of Cellulolytic Complexes Sourced from Thermophilic Aspergillus Strains

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

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

Abstract: The industrial saccharification of lignocellulose into simple glucose syrups requires robust cellulolytic enzymes that can resist thermal denaturation during high-temperature steam hydrolysis loops. This study details the isolation, microstructural profiling, and kinetic optimization of high-yielding endoglucanase complexes produced by a thermophilic fungal strain sourced from processing soil surrounding artisanal rice hulling mills. Enrichment culturing was executed in cellulose-infused Mandels' media at 50°C, isolating a dominant strain identified via internal transcribed spacer (ITS) rRNA gene sequencing as Aspergillus terreus strain Rice-C1. Response surface methodology optimized solid-state fermentation yields using wheat bran matrices. Maximum cellulase activity (54.5 U/mL) was achieved at an incubation temperature of 50°C, an initial substrate pH of 6.0, 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 7.0 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: Endoglucanase; Aspergillus terreus; Solid-state fermentation; Thermal stability; Kinetic optimization; Cellulose saccharification

Manuscript Timeline: Received: March 10, 2019; Revised: April 18, 2019; Accepted: May 14, 2019; Published: November 02, 2019.

Citation: Nwosu, C. N., & Sato, H. M. (2019). Isolation, Structural Profiling, and Optimizing Kinetics of Cellulolytic Complexes Sourced from Thermophilic Aspergillus Strains. International Journal of Chemistry, 10(11), 81–88.

Subscribe to read the full article: https://www.internationalscholarsjournals.org/subscribe-to-read