Cellulolytic fungi from degraded woods of Arasbaran forest, Iran

Abstract

Cellulose is the most abundant component of lignocellulose with a vast range of applications in various fields such as nanotechnology, pharmacy, food industry. The cellulase enzyme complex consists of three major enzymes, including endoglucanases, exoglucanases, and beta-glucosidases, which are capable of decomposing cellulose. In this study, various fungal species were isolated from the degraded woods of Arasbaran forests. The activity zone technique was used to screen cellulolytic fungi. Based on the results, three fungal isolates had the highest cellulolytic activity. Phylogenetic analysis was performed based on the Internal Transcribed Spacer (ITS) region and the isolates were classified into two genera as follows: Trichoderma and Aspergillus. The cellulolytic activity of three fungal isolates was measured by the DNS method and indicated thatT. harzianum has the highest activity (22.3 U/mg) compared with other isolates. Afterward, the growth condition of T. harzianum was optimized by Response Surface Methodology (RSM) to obtain a high amount of cellulase activity. The results indicated that the maximum amount of cellulase production (38.3 U/mg) was observed at 1.5% CMC, 0.51% peptone, pH 5, temperature 26.4°C, and incubation for about 3 days. Therefore, T. harzianum could be considered as a potential candidate for genetic improvement and enzyme production.