Isolation of Xylanase Producing Strains, Optimization of Fermentation Conditions and Research on Enzymatic Properties

Ji Huilong,Ma Zhuang,Wu Wenxuan,Gao Xin,Qing Qing

doi:10.5296/jbls.v12i2.18483

Abstract

In this study, we successfully isolated a strain of Aspergillus oryzae TR08, which produced xylanase secreted to the outside of the cell productively. The enzyme activity and specific activity in the fermentation broth of this strain reached peak values of 451 IU/mL and 1963 IU/mg after 156 h of fermentation. A single factor experiment was designed, and it was found that the strain was adjusted to the initial pH of the fermentation broth to 7.5 in a shaker at 180 rpm and 32 °C. After 156 h of fermentation, the enzyme activity reached a maximum of 1264 IU/mL. The optimal reaction temperature and pH value of the xylanase were 55 °C and 7.5, respectively, and it had excellent acid and alkali resistance and a wide pH activity range. The xylanase was increased the catalytic activity by 15% in 0.25 mM Fe3+, and the biological activity of the enzyme was not affected in the sodium dodecyl sulfate environment.

Highlights

In this study, we successfully isolated a strain of Aspergillus oryzae TR08, which produced xylanase secreted to the outside of the cell productively
The xylanase was increased the catalytic activity by 15% in 0.25 mM Fe3+, and the biological activity of the enzyme was not affected in the sodium dodecyl sulfate environment
An Aspergillus oryzae strain TR08 that secretes xylanase from the soil was successfully isolated

Summary

Introduction

We successfully isolated a strain of Aspergillus oryzae TR08, which produced xylanase secreted to the outside of the cell productively. Pretreatment combined with enzyme method, the extracted xylan was pretreated by acid, alkali or hydrothermal method, and xylanase was used to catalyze the production of XOS with the target degree of polymerization (Qian et al, 2020). This method produced the usual xylose content in XOS that was high, the cost of enzymes was high, but the degree of polymerization was more consistent. In order to find the most suitable application conditions, the enzyme solution obtained under the optimal fermentation conditions was used to study the properties of xylanase in the solution, which provided experimental and theoretical basis for the production and application of xylanase

Objectives

Methods

Results

Conclusion