Abstract
An important integral part of the physiology of the fungal cell is the nature of the cascade of extracellular enzymes produced by fungi. A tropical strain Aspergillus flavus Link obtained from deteriorated tomato (Solanum lycopersicum) fruits grew in a growth nutrient medium composed of MgSO4.7H20, K2HPO4, KH2PO4, FeSO4.7H2O, potassium nitrate and starch at 30oC. Extracellular proteins produced by the isolate in the medium expressed α-amylase activity. The enzyme was partially purified by ammonium sulphate precipitation followed by dialysis. The enzyme exhibited optimum activity at 35oC and at pH 6.0. It possessed an apparent Km of 7.1 mg/ml for the hydrolysis of starch. The enzyme was stimulated by Na+ and Ca2+ but inhibited by ethylenediamine tetraacetic acid and 2,4-dinitrophenol. It lost 64.1% of its activity within 20 min of heating at 80oC. Of the nitrogenous compounds potassium nitrate, ammonium sulphate and casein, casein as nitrogen source in the defined growth medium with starch as carbon source supported most activity of α-amylase by the fungal isolate. Observations during the partial purification and characterization of the enzyme are herein reported.
Highlights
Amylases are hydrolytic enzymes that catalyze the degradation of starch molecules and other carbohydrates to yield dextrins and progressively smaller polymers composed of glucose units (Bohinski, 1983; Reddy et al, 2003)
The tropical fungal strain Aspergillus flavus Link for this investigation was isolated from deteriorated tomato (Solanum lycopersicum) fruit obtained from Cocoa Research Institute, Ibadan, Nigeria (CRIN)
The tropical fungal strain Aspergillus flavus Link isolated from deteriorated tomato (Solanum lycopersicum) fruit was grown in a defined growth medium with specific nitrogen and carbon sources of fungal growth
Summary
Amylases are hydrolytic enzymes that catalyze the degradation of starch molecules and other carbohydrates to yield dextrins and progressively smaller polymers composed of glucose units (Bohinski, 1983; Reddy et al, 2003). They can be of animal, plant or microbial sources (Wu et al, 2004; Rahardjo et al, 2005). Amylase is a key enzyme involved in digestion and carbohydrate metabolism in silkworm and its activity is related to productivity traits. This work is aimed to study the effect of cultivation conditions such as temperature, pH, and composition of nutrient growth medium such as substrate concentrations, certain cations and specific inhibitors on increase of activity of
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
