الفهرس Only 14 pages are availabe for public view
 |  | from | 237 |  |  |
| | | from | 237 | | |
Abstract
Fifty-nine fungal species were isolated from three soil samples. The ability of
growth on cellulose as sole carbon source was studied. Cellulolytic isolates
represent 90%,87.5% and 95.6% in soil samples. The most active isolates obtained
were used to determine (CMCase) when grown on cotton or wood. In soil sample
No. (1), the most active fungal isolates were Aspergillus sp. (A W) and Aspergillus
sp. (T4) while Aspergillus sp. (T 5) was the most active isolate in soil sample No. (2).
In soil sample No. (3), there were three fungal isolates showed high CMCase
activity. The most active isolates were identified as Aspergillus candidus (A W), 3
isolates of Aspergillus terreus (T2, T4 and T5) Trichoderma sp (Tri) and
Penicillium purpurogenum (R). (RAPD) was used to investigate the polymorphism
within isolates. The results showed that total number of amplified bands were (243).
18S rRNA from all isolates were amplified. Purified PCR products were used in
sequencing reactions. Aspergillus candidus (A W) from soil No.1, Aspergillus
terreus (T5) from soil No.2 and Trichoderma sp. (Tri) from soil No.3 were selected
to determine the factors affecting the CMCase production. Trichoderma sp. (Tri)
was the most active isolate on wood and cotton. The obtained protein pattern
revealed that, the CMCase system contains 2 protein components namely CMCase I
(58 KDa) and CMCase 11 (34 KDa). The optimum specific activities of CMCase I
and 11 obtained at substrate concentration of 1 %. CMCase activities reaching the
optimum values at 50°C for both enzymes. The obtained results showed also that
the specific activities increase with the increasing of the pH value of the reaction
mixtures till reaching to their maximal values at pH 5.0 for both CMCase I and 11.
CoCh was the most inhibitory ion for CMCase I while HgCh was the most
inhibitory ion for CMCase 11.