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Production of amylase by Aspergillus foetidus on rice flour medium and characterization of the enzyme
Author(s) -
Michelena V.V.,
Castillo F.J.
Publication year - 1984
Publication title -
journal of applied bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 0021-8847
DOI - 10.1111/j.1365-2672.1984.tb01367.x
Subject(s) - starch , amylopectin , amylose , maltose , food science , amylase , chemistry , corn steep liquor , enzyme , alpha amylase , aspergillus niger , enzyme assay , ammonium , maize starch , biochemistry , fermentation , sucrose , organic chemistry
M ichelena , V.V. & C astillo , F.J. 1984. Production of amylase by Aspergillus foetidus on rice flour medium and characterization of the enzyme. Journal of Applied Bacteriology 56 , 395–407. Aspergillus foetidus ATCC 10254 was selected from nine starch‐utilizing microorganisms for its high amylolytic activity. This mould produced high levels of extracellular α‐amylase in rice starch medium and degraded the available starch efficiently. Optimal conditions for enzyme production on 2.0% rice medium included 28d̀C, initial pH of 6.6, and supplementations with 0.02% NaNO 2 , 0.08% KH 2 PO 4 , and 0.08% corn steep liquor. Eleven‐fold purification of the enzyme was obtained after ammonium sulphate and ethanol precipitations from spent medium. The molecular weight was estimated at 41 500. Optimum pH and temperature for enzyme activity were 5.0 and 45d̀C. Michaelis‐Menten constants were 1.14 mg/ml on amylopectin, 2.19 mg/ml on soluble starch and 7.65 mg/ml on amylose. Amylose produced substrate inhibition while glucose or maltose did not inhibit the enzyme. This α‐amylase may be used as a saccharifying enzyme for rice starch. Aspergillus foetidus ATCC 10254 also presents a potential for treatment of starch‐containing waste waters.