Isolation of amylase producing fungi from cassava flour

Amylases are among the most important enzymes with potential applications in the present-day industry. Thus, isolating pure culture from cassava as the cheap source has manifold importance for food industries. In the present study, eleven amylase producing fungal strains were isolated from cassava flour and growth pattern, as well as optimum growth condition, was determined. All isolates showed amylases activity but isolate BR005, BR001 and GR003 recorded maximum clear zone diameters of 54.75 ± 0.957 mm, 53.25 ±0.645 mm 51.5 ± 1.414 mm, respectively. The submerged fermentation method was employed for crude amylase and biomass production. There were significant differences (p˂0.05) in starch concentrations and growth rates between the three isolates. GR003 and BR005 attained their optimal amylase activities of 4.23±0.25 U/mL and 3.75±3.16 U/mL at 50 °C, respectively, whiles BR001 attained its optimum amylase activity of 3.43±0.77 at 60 °C. Whereas, BR005, BR001 and GR003 attained their optimal amylase activity of 5.14±1.99 U/mL, 4.53±0.01 U/mL and 1.25±1.11 U/mL at a pH range of 6 to 7, making them neutrophilic fungi. Moreover, isolates BR005, BR001 and GR003 recorded the highest amylase activities of 4.31±0.14U/mL, 4.67±1.16±U/mL and 3.16±0.12U/mL at the starch concentrations of 3%, 2%, and 2.5% and fermentation period of 48 h, 66 h and 42 h, respectively. Lastly, BR005, BR001 and GR003 achieved their optimal amylase activities of 5.41±0.11U/mL, 6.24±0.14 U/mL and 6.22±0.12 U/mL at 48 h, 66 h and 42 h of incubation, accordingly. Indicating that cassava flour is a good source of amylolytic fungi with a potential application under wide conditions.