Production and characterization of extracellular α-amylase produced by Wickerhamia sp. X-Fep.
A yeast isolate able to produce high levels of extracellular α-amylase was selected from a collection of 385 yeasts and identified as Wickerhamia sp. by the sequence of the D1/D2 domain of the 26 S rDNA gene. Part of the nucleotide sequence of the amy1-W gene was cloned, and a sequence of 191 amino acids deduced from this gene was analyzed. The peptide contains three characteristic well-conserved regions in the active sites of α-amylases (EC 3.2.1.1). The enzyme was purified and in situ activity showed only one band with amylolytic activity. The molecular mass of the α-amylase was estimated at 54 kDa by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Enzymatic activity on soluble starch as substrate was optimal at pH 5-6 and 50 °C. This thermostable enzyme was inhibited by EDTA-Na(2) and 1,10-phenanthroline; the activity of the dialyzed enzyme was reactivated with Ca(2+) and Mg(2+) cations, which indicates that the α-amylase is a metalloenzyme. α-Amylase production was induced by starch and maltose and repressed by glucose. The high yield and productivity found in this work makes this Wickerhamia sp. strain a promising candidate for the biotechnological production of α-amylase.
Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Plan de Ayala y Prol. de Carpio s/n, Col. Casco de Santo Tomás, Agencia de Correos 220, Mexico City, CP 11340, Mexico.
Zahuiti
Z
Hernández-Montañez
Margarita
M
Juárez-Montiel
Martha
M
Velázquez-Ávila
Eliseo
E
Cristiani-Urbina
César
C
Hernández-Rodríguez
Lourdes
L
Villa-Tanaca
Griselda
G
Chávez-Camarillo
D000595:Amino Acid Sequence; D001203:Ascomycota / Q000166:cytology / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D019149:Bioreactors / Q000382:microbiology; D005110:Extracellular Space / Q000201:enzymology*; D005800:Genes, Fungal / Q000235:genetics; D007700:Kinetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D016415:Sequence Alignment; D013379:Substrate Specificity; D000516:alpha-Amylases / Q000096:biosynthesis* / Q000737:chemistry
D000516:alpha-Amylases