Background: Inulinase is a versatile enzyme from glycoside hydrolase family which targets the β-2, 1
linkage of fructopolymers. In the present study, the effect of medium composition and culture
conditions on inulinase production by
Aspergillus niger
ATCC 20611 was investigated in shake-flasks.
Results: The highest extracellular inulinase (3199 U/ ml) was obtained in the presence of 25% (w/v)
sucrose, 0.5% (w/v) meat extract, 1.5% (w/v) NaNO
3 and 2.5 mM (v/v) Zn
2+, at initial pH of 6.5,
temperature 35ºC and 6% (v/v) of spores suspension in the agitation speed of 100 rpm. Surfactants
showed an inhibitory effect on enzyme production. The optimum temperature for inulinase activity was
found to be 50ºC. TLC analysis showed the presence of both exo- and endo-inulinase.
Conclusion:
Sucrose, Zn
2+, and aeration were found to be the most effective elements in inulinase production by
A.
niger ATCC 20611. TLC analysis also showed that the crude enzyme contained both endo and exoinulinases.
The strain is suggested as a potential candidate for industrial enzymatic production of
fructose from inulin.
