Xylanolytic enzyme production by an Aspergillus niger isolate

Area of Science:

• Biotechnology
• Enzyme Technology

Background:

• Xylanolytic enzymes are crucial for breaking down xylan, a major component of plant biomass.
• Aspergillus niger is a well-known producer of various industrial enzymes, including xylanolytic enzymes.
• Optimizing enzyme production without chemical inducers is desirable for cost-effective industrial applications.

Purpose of the Study:

• To investigate the production of xylanolytic enzymes by Aspergillus niger CCMI 850 in batch cultures.
• To evaluate the impact of fermentation medium composition on enzyme activity without chemical inducers.
• To characterize the produced beta-xylanase for potential industrial applications.

Main Methods:

• Cultivation of Aspergillus niger CCMI 850 in batch cultures using xylan as the carbon source.
• Assay of beta-xylanase, beta-xylosidase, alpha-L-arabinofuranosidase, and total cellulase activities.
• Optimization of fermentation conditions (pH, temperature) for beta-xylanase activity.
• Partial characterization of beta-xylanase, including determination of Km and Vmax.

Main Results:

• Achieved a high beta-xylanase activity of approximately 65 U/mL using 4% xylan as the carbon source.
• Total cellulase activity was undetectable under the tested conditions.
• The beta-xylanase activity reported is the highest for a wild-type strain of Aspergillus niger.
• Determined kinetic parameters (Km = 0.3 mM, Vmax = 19 µmol/min) for beta-xylanase using insoluble birchwood.

Conclusions:

• Aspergillus niger CCMI 850 is a highly efficient producer of beta-xylanase without chemical induction.
• The produced beta-xylanase exhibits significant activity and favorable kinetic properties.
• The crude beta-xylanase preparation holds promise for applications in the pulp and paper industry.