The effect of some environmental conditions on the growth and activity of the external enzymes for five sp. of Fusarium


A Laboratory studies are conducted to determine the influence of environmental parameters (temperature, pH, light regime and type of growth medium) on growth of five species of Fusarium fungi. The highest growth of F.oxysporum and F.solani is obtained at 25˚C and gives growth (8 and 7.5 cm respectively) after 6 days of incubation. In contrast Fusarium proliferatum reveals maximal growth (8 cm) at 30˚Cduring the same period while, the F.sacchari and F.globosum grow well at 20˚C. The optimum pH for growth of all species of Fusarium is obtained at 7.5. F.oxysporum and F.solani reveals best growth on SDA. Whereas, F.globosum, F.proliferatum, and F. sacchari are showed higher growth on CDA. The growth of all studied fungi is reduced significantly under continuous light compared with that grow at dark period. The ability of Fusarium species for producing extracellular enzymes (protease and cellulose) is examined by using CMC and skim milk. Among all tested species, F.oxysporum and F.sacchari was showed high protease activity at the third day of incubation, compared with F.globosum, F. proliferatum and F. solani which reveals less activity for protease. The experiment suggested strong chitinase activity F.oxysporum and F.sacchari, while other species of Fusarium showed least activity. Furthermore, cellulose activity for all species of Fusarium are detected.