Improved Cellulolytic Activity of <i>Alternaria citri</i>: Optimization and EMS Treatment for Enhanced Cellulase Production

Abstract

Fungal species secrete various enzymes and are considered the primary sources of industrially important cellulases. Cellulases are essential natural factors for cellulose degradation and have attracted significant interest for multiple applications. However, reducing the cost and enhancing cellulase production remains a significant challenge. Mutagenesis has opened a new window for enhancing enzyme secretion by modifying the organism’s genome. In this study, cellulases from Alternaria citri were produced and characterized, and the optimization for ideal fermentation conditions was performed for three types of cellulases (endoglucanase, exoglucanase, and β-glucosidase) by a wild-type (A. citri) and a mutant strain (A. citri 305). Ethyl methanesulfonate, a chemical mutagen, was used to enhance cellulase production by A. citri. The results demonstrate the improved cellulolytic ability of the mutant strain A. citri 305 utilizing lignocellulosic waste substances, particularly, orange-peel powder, wheat straw, sugarcane bagasse, and sawdust, making this study economically valuable. This evokes the potential for multi-dimensional applications in enzyme production, waste degradation, and biofuel generation. This study highlights that the activity of cellulases to hydrolyze various lignocellulosic substrates is enhanced after mutagenesis.

Keywords

• <i>alternaria citri</i>
• endoglucanase
• exoglucanase
• β-glucosidase
• ethyl methanesulfonate
• mutagenesis