OPTIMAL CONDITIONS FOR THE PRODUCTION OF INDUSTRIAL ENZYMES BY ASPERGILLUS NIGER USING AGRICULTURAL WASTES AS SOURCE OF CARBON

Abstract

Optimal conditions of cultural medium in submerged fermentation were studied for the production of industrial enzymes Invertase, ?-Amylase and Glucose isomerase from Aspergillus niger using agricultural wastes (sunflower waste, cotton stalk and rice husk from fields of Interior Sindh) as sources of carbon. Effects of incubation time period (24-240 hours), source of nitrogen (Corn steep, Casein Peptone Potassium Nitrate Albumin A. Sulphate Urea Yeast Extract), pH (4-9) and temperatures (40-60°C) were also investigated for optimum enzymes production. It was found that the strain produced the highest level of Invertase (6.92 U/mL) in culture medium containing yeast extract as a source of nitrogen; 0.6N H2SO4 hydrolysed sunflower waste as a source of carbon after 96h of incubation at initial pH 8 and temperature 40°C. pH and thermo stable strain can be used for Invertase production in industries. Although ?-amylase and glucose isomerase were also produced by the strain and even their activities (?-Amylase 0.78 U/mL; Glucose isomerase 0.69 U/mL) were enhanced by nitrogen sources but activities were too low for the utilization in industries.