Plant residues contain nutrients required for the growth of bacteria and fungi. Use of agro industrial wastes or residues to cultivate fungi for enzymes production is an economical method combined with waste recycling. In this study, agro industrial residues were used as fermentation medium for amylase production by Aspergillus niger. Cultivation temperature in the range of 20°C, 25°C, 30°C, 35°C and 40°C was considered as the fermentation factor to optimize the enzyme production. The wastes used were one of the following materials at a substrate concentration of 100g: wheat bran, ragi husk, coconut shell, bagasse, paddy straw and ground nut shell and the fermentation was carried out for a period of 14 days. The results revealed that all the substrates promoted the growth of A. niger and ragi husk was proved to be the best growth medium that secured the highest amylase activity. The highest enzyme production of 213U ml-1 was observed at 25°C and the enzyme activity was consistent in fermentation media containing ragi husk and paddy straw as substrates. Most of the substrates tested in this study were utilized by A. niger within 7 days of solid state fermentation for the production of amylase. However, utilization of ragi husk as the substrate needed more fermentation time and at the same time it has resulted in highest enzyme activity. In consideration of the results, agro industrial residues could be used as economical medium for the production of fungal amylases by solid state fermentation.
Author(s): Sibi G