Abstract

ESPINEL, Esperanza  and  LOPEZ, Elizabeth. PURIFICATION AND CHARACTERIZATION OF a-AMYLASE FROM PENICILLIUM COMMUNE PRODUCED BY SOLID STATE FERMENTATION. Rev.Colomb.Quim. [online]. 2009, vol.38, n.2, pp.191-208. ISSN 0120-2804.

This study reports the purification and partial characterization of an a-amylase from Penicillium commune produced by solid state fermentation using colombian white tapioca (Manihot esculenta Crantz) as support. The enzyme was purified by ammonium sulphate precipitation, anion exchange chromatography (DEAE-Sep-hadex A-50), gel filtration chromatography (Sephadex G-75) and cation exchange chromatography (CM-Sephadex C-50). A purification factor of 62 with a 9% yield and final specific activity of 314.82 U/mg were recorded. Purification to homogeneity was confirmed by SDS PAGE. The molecular weight was estimated to be 35 kDa. The enzyme shows maximal activity in the soluble starch hydrolysis at pH 6.0, and is stable in a range of pH from 5.0 to 7.0. Thermal stability was in the range of temperature from 0 to 50 °C, and its optimal temperature was 70 °C. Ions Ca²⁺,Ba²⁺ and Ag⁺ significantly increase the activity of the enzyme, with ion Ca²⁺ as the highest activator. Cu²⁺ does not alter significantly the activity of the enzyme, whereas Li⁺ and Fe³⁺ decrease it slightly (13%) and Co²⁺ and Hg²⁺ decrease it 25% and 40% respectively. Km = 0.48 mg/mL and Vmax = 5.85 /xmol glucose/min were calculated using the linearization of Lineweaver-Burk. Among hydrolysis products of tapioca starch are maltose and glucose, this result provides evidence of the enzyme ability to hydrolyze the starch a-1,4 glucosidic linkages, a characteristic behavior of an a-amylase.

Keywords : a-amylase; Penicillium commune; solid state fermentation; colombian white tapioca.

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