Isolation, purification, and enzymatic activity of cellulase components of the fungus Aspergillus terreus

Abstract

The accumulation dynamics of cellulolytic enzymes in culture media of the basidiomycete fungi Panus tigrinus, Pleurotus ostreatus, Fomes fomentarus, and the micromycete Aspergillus terreus were studied during a long incubation period. It was found that A. terreus was the most active producer of cellulolytic enzymes among the studied fungi. Two protein fractions with cellulase activity were isolated using gel filtration and ion-exchange chromatography. PAAG electrophoresis showed that fraction-I consisted of four components; fraction-II, an electrophoretically homogeneous protein.It is known that cellulolytic enzymes are produced by various microorganisms belonging to various taxonomic groups [1,2]. Cellulases have broad applications and are used mainly in food, textile, chemical, medical, pharmaceutical, paper, and wood processing industries. They are also added to animal feed and to agricultural process wastes [3][4][5][6].The goal of our work was to study the ability of wood-destroying fungi to produce highly active cellulases and to produce active preparations of cellulolytic enzymes.The accumulation dynamics of cellulolytic enzymes in culture media of the fungi Panus tigrinus, Pleurotus ostreatus, Fomes fomentarus, and Aspergillus terreus were determined during different periods of the growth and development, from 7 to 14 days.The results show that A. terreus was the best producer of cellulase compared with the other fungi. The maximum endoglucanase activity was observed 10 days from the start of growth. Therefore, 10-day culture liquid of A. terreus was first filtered through glass wool and then through a millipore filter (0.2 µm pore size) to separate the supernatant from the cell culture in order to isolate enzyme components of the cellulase complex. Cellulase activity in solution was determined by the Wood and Bhat method [7] using Na-CMC (1%) as substrate. The solution (220 mL) contained 106.1 units of total cellulase activity ( Table 1).The protein concentration determined by the Lowry method [8] indicated 154 mg of protein in the collected culture medium from A. terreus. The specific activity of the cellulolytic enzyme in the culture medium was 0.688 U/mg of protein.Then the culture medium was concentrated in a rotary evaporator to 17 mL. The total cellulase activity and protein concentration in the concentrated enzyme solution was 83.38 U and 108.56 mg, respectively. Analysis of the proteins by SDS-PAAG electrophoresis showed nine protein bands with molecular weights from 17 to 120 kDa in the concentrated enzyme solution.

Adsorption of Cellulase Isolated fromAspergillus Nigeron Chitosan/Alginate Particles Functionalized with Epichlorohydrin

“…In the case of cellulase, to our knowledge, there are no such studies to recover the enzyme, apart from conventional salt precipitation techniques and ion-exchange or gel permeation chromatography using state-of-the-art polymeric resins (Avelino et al 1999;Roy et al 1999;Amritkar et al 2004;Mirzaakhmedov et al 2007;Wang et al 2009). …”

“…Even though these biopolymers have been widely reported individually for purification of bioproducts (Shi et al 2003;Hoven et al 2007;Torres et al 2007;Feng et al 2009;Xu et al 2009), very few records exist regarding their combined use for biomolecule adsorption. In the case of cellulase, to our knowledge, there are no such studies to recover the enzyme, apart from conventional salt precipitation techniques and ion-exchange or gel permeation chromatography using state-of-the-art polymeric resins (Avelino et al 1999;Roy et al 1999;Amritkar et al 2004;Mirzaakhmedov et al 2007;Wang et al 2009).…”

A unique fungal strain collection from Vietnam characterized for high performance degraders of bioecological important biopolymers and lipids

“…Members of the genus Fusarium are common in plants as endophytes and pathogens and have been described as producers of active cellulases [ 64 ]. Fusarium oxysporum and Aspergillus terreus were described with a slightly more effective cellulase with a specific activity of 0.9 U/mg [ 65 ], and 0.56–0.85 U/mg, respectively [ 66 , 67 ]. By checking the CAZy database only one putative cellulose (GH5) from Fusarium solani (more related to FW16.1) was found [ 68 ].…”

Isolation and characterization of efficient cellulolytic fungi from degraded wood and industrial samples

“…However, Penicillim species are inferior to three of the present isolates. According to Mirzaakhmedov et al (2007), A. terrus was the most active producer of cellulolytic enzymes than Penicillum, Fusarium, Trichoderma and other Aspergillus species. The present study also indicated that A. terrus was better than Penicillium species, though inferior to Isolate 'E' and Alternaria species.…”