Extracellular amylase production of a thermotolerant Fusarium sp: isolated from Eastern Nigerian soil

ABSTRACT

In this work, an α- amylase producing Fusarium sp. was isolated from the soil at 50 0C. Growth and enzyme production occurred at 30, 45 and 55 ºC. Soybean meal at 1 percent concentration, supplemented with 0.2 percent NH4Cl and 2.5 percent corn starch elicited the highest amylase yield. Optimum pH for the enzyme was pH 6.5 which retained over 60 percent of its activity after 24 h incubation at the pH range of 4.5-7.0. The enzyme showed high activity from 40-70 0C with optimal activity at 50 ºC and 78 percent activity was retained after incubation at 70 ºC for 30min. Catalytic function of the crude amylase was stimulated by Mg (136 percent), Ca (118 percent) and Zn (118 percent) at 2mM concentrations. The enzyme hydrolyzed cassava, potato and yam starches effectively.