Partial Purification, Biochemical Characterization and Biotechnological Application of Cellulase Isolated from Aspergillus niger for Juice Clarification

Abstract

Cellulase enzymes are key biocatalysts with wide industrial relevance, particularly in food and beverage processing. Despite its significance, efficient production and purification methods are still needed to meet industrial demands. Recent studies have explored the cellulose-degrading potential of bacteria and fungi associated with Long-horned beetles, highlighting their promising role as a novel source of cellulases. Aspergillus niger, isolated from the gut of Long-horned beetles, presents a promising new source of cellulase with potential for enhanced stability and activity. Therefore, this study sought to investigate the purification, characterization, and biotechnological application of cellulase produced by Aspergillus niger isolated from the gut of the Long-horned beetle (Cerambycidae latreille). The fungus was cultivated under optimized submerged fermentation conditions, and the crude cellulase extract was purified using ammonium sulfate precipitation followed by ion-exchange chromatography. The purification process resulted in a significant increase in specific activity and enzyme yield. Characterization of the partially purified enzyme was performed to assess the effects of various inhibitors, including sodium nitrate, SDS, Tween 20, β-mercaptoethanol, cysteine, urea, Triton X, and EDTA, on enzymatic activity. Kinetic parameters (Km and Vmax) were determined using cellulose as substrate at varying concentrations, demonstrating high substrate affinity and catalytic efficiency. The enzyme’s potential for industrial application was evaluated through juice clarification tests using apple, pineapple, orange and watermelon juices. The findings revealed that cellulase treatment markedly improved juice clarity, reduced viscosity, and enhanced filterability without compromising nutritional quality. Overall, cellulase from A. niger isolated from Cerambycidae latreille represents an eco-friendly and efficient biocatalyst suitable for large-scale juice clarification and other biotechnological processes.