Premium
High Specific Activity of Raw‐Starch Digesting‐Glucoamylase Producing Rhizopus sp. A‐11 in Liquid Culture
Author(s) -
Morita H.,
Fujio Y.
Publication year - 1997
Publication title -
starch ‐ stärke
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.62
H-Index - 82
eISSN - 1521-379X
pISSN - 0038-9056
DOI - 10.1002/star.19970490709
Subject(s) - starch , ammonium sulfate precipitation , chemistry , raw material , sephadex , chromatography , protease , enzyme , ammonium sulfate , rhizopus , food science , enzyme assay , yield (engineering) , biochemistry , rhizopus oryzae , size exclusion chromatography , fermentation , organic chemistry , materials science , metallurgy
Glucoamylase (GA) (EC 3.2.1.3) from Rhizopus sp. A‐11 using metalion regulated liquid medium was purified by ammonium sulfate precipitation and column chromatography on CM‐Sephadex C‐50. Since purification was easy, the enzyme was purified about 5.0 fold with a 72.9% yield. The enzyme was proved to be homogeneous as judged by SDS‐PAGE, and has a molecular weight of about 72.4kDa. The enzyme strongly digested against raw starches. Raw cassava, wheat, and corn starch digesting relative specific activities of the purified enzyme were 15, 13, and 15%, respectively, as compared with soluble starch digesting specific activity (21,360 units/mg protein). Raw cassava, wheat, and corn starch adsorption rates were 99,99, and 99%, respectively. This culture produced little acid or neutral protease. According to the high raw starch digesting activity, high raw starch adsorption rate, low protease activity, and high molecular weight of the GA, it may be classified as GA‐I. Most proteins in the culture were GA. These results suggest a considerable advantage for GA production by liquid cultivation.