Isolation of local potential fungus capable of degrading mannan was explored from various sources of soil sample collected from agricultural areas. The isolates were screened based on the clearing zone method on selective agar media containing guar gum as substrate. A total of 40 isolates were screened and only 10 had activity ratio ranging from 1.6 mm to 3 mm which were used for further analysis. These isolates were incubated in shake flasks at 30 °C for 48 h having minimal media and 1% guar gum as substrate. The best enzyme producer was isolate AZF8 with mannanase enzyme acitivity of 108 U/ml. The isolate AZF8 was identified as Aspergillus nidulans and was further used for the production of mannanase from agroresidues. Different agroresidues were screened for mannanase production of which soy straw supported maximum mannanase production with enzyme activity of 80.18 U/ml.
