Newly isolated Aspergillus niger that was provided by Dr. Bilqees Fatima, Assistant Professor Botany Department Minhaj University Lahore.
Seven different kinds of agro-industrials substrates was used such as wheat bran, wheat straw, rice straw, sugar cane, brassica napus, gram testa and oat. All of these substrates was brought from local market of Lahore. Ten gram of each substrate was used in this study and 10ml of distilled water was added in it.
3.8g of potato dextrose ager (PDA) was dissolved in a beaker containing 100ml of distilled water on hot plate. 5ml of media was poured in each test tube and covered with cotton- plug and sterilized by autoclaving at 15psi for 15min and than kept the test tubes on slanting position and left undisturbed until the ager solidified.
Refreshing the culture A.niger was inoculated on slant containing PDA for growth. Heat…show more content… These two reagent was prepared separately and then mixed together. The reaction mixture which was composed of 0.1ml of enzyme, 1ml of starch solution and 2ml of DNS reagent . Starch solution was prepared by adding 0.5g of starch in 50ml of phosphate buffer and the dissolved by heating. 1ml of diluted crude enzyme and 1ml of starch solution was mixed in 20ml of test tube and then incubated in water bath for 15min at 60ºC then cooled the test tube then 2ml of DNS reagent was added in the mixture and boiled in a beaker on hot plate for 20min. The volume of reaction mixture was maintained up to 16ml by adding distilled water. Finally, the test tubes were cooled and the optical density of the resulting colored solution was measured at 540 nm against a reagent blank for calibration on spectrophotometer in visible region and the results were