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The glucoamylase from Aspergillus wentii : Purification and characterization
Author(s) -
Lago Munira C.,
Santos Fabiane C.,
Bueno Paulo S. A.,
Oliveira Marco A. S.,
BarbosaTessmann Ione P.
Publication year - 2021
Publication title -
journal of basic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.58
H-Index - 54
eISSN - 1521-4028
pISSN - 0233-111X
DOI - 10.1002/jobm.202000595
Subject(s) - chemistry , starch , hydrolysis , chromatography , enzyme , size exclusion chromatography , aspergillus awamori , enzyme assay , molecular mass , biochemistry
Abstract This study describes for the first time the purification and characterization of a glucoamylase from Aspergillus wentii (strain PG18), a species of the Aspergillus genus Cremei section. Maximum enzyme production (∼3.5 U/ml) was obtained in submerged culture (72 h) with starch as the carbon source, at 25°C, and with orbital agitation (100 rpm). The enzyme was purified with one‐step molecular exclusion chromatography. The 86 kDa purified enzyme hydrolyzed starch in a zymogram and had activity against p ‐nitrophenyl α‐ d ‐glucopyranoside. The optimal enzyme pH and temperature were 5.0 and 60°C (at pH 5.0), respectively. The T m of the purified enzyme was 60°C, at pH 7.0. The purified glucoamylase had a K M for starch of 1.4 mg/ml and a V max of 0.057 mg/min of hydrolyzed starch. Molybdenum activated the purified enzyme, and sodium dodecyl sulfate inhibited it. A thin layer chromatography analysis revealed glucose as the enzyme's main starch hydrolysis product. An enzyme's peptide sequence was obtained by mass spectrometry and used to retrieve a glucoamylase within the annotated genome of A. wentii v1.0. An in silico structural model revealed a N‐terminal glycosyl hydrolases family 15 (GH15) domain, which is ligated by a linker to a C‐terminal carbohydrate‐binding module (CBM) from the CBM20 family.