Abstract
In this work optimization parameters in submerged fermentation were studied for the production of Invertase from Aspergillus flavus (Link 1809; IBGE 07) using agricultural based by-products (sunflower waste, cotton stalk, rice husk, date syrup and molasses) as sources of carbon. Effects of incubation time period (24-240 h), various cultural media (CM1, CM2, CM3, CM4 and CM5) sources of nitrogen (Corn steep, Casein, Potassium Nitrate Albumin Ammonium Sulphate Urea and Yeast Extract), pH (4.0-9.0), temperatures (30-70° C), inoculum size (4x106 -8x106 conidia) and agitation rate (50-300 rev/min) were also investigated for maximum invertase production. Optimal conditions for the production of invertase (7.41 U/mL) by Aspergillus flavus were observed when the strain was grown on culture medium CM1 containing yeast extract as a source of nitrogen, molasses as a source of carbon after 48 h of incubation at initial pH 6.5, temperature 40° C, inoculum size of 6x106 conidia in 50 mL of culture medium and agitation rate of 200 rev/min.
