AMYLASES PRODUCED BY A THERMOPHILIC FUNGU S, THERMOASCUS-AURANTIACUS,AND SOME OF THEIR PROPERTIES

Citation
N. Ohno et al., AMYLASES PRODUCED BY A THERMOPHILIC FUNGU S, THERMOASCUS-AURANTIACUS,AND SOME OF THEIR PROPERTIES, Seibutsu kogaku kaishi, 76(3), 1998, pp. 111-117
Citations number
28
Language
GIAPPONESE
art.tipo
Article
Categorie Soggetti
Food Science & Tenology","Biothechnology & Applied Migrobiology
Journal title
ISSN journal
0919-3758
Volume
76
Issue
3
Year of publication
1998
Pages
111 - 117
Database
ISI
SICI code
0919-3758(1998)76:3<111:APBATF>2.0.ZU;2-8
Abstract
A thermophilic fungus, Thermoascus aurantiacus IFO 31693, produced amy lases extracellularly. For the production of amylases, the addition of 2 to 4% starch as a carbon source and of 0.5% sodium nitrate as a nit rogen source were effective. Two amylases were purified from the cultu re filtrate of the organism incubated in a 2% starch medium for 6 d at 40 degrees C. One (amylase I-b) was obtained as a partially purified protein (M-r, about 75,000) and the other (amylase II) as an electroph oretically homogeneous protein (M-r, about 56,000). Amylases I-b and I I were respectively identified as being exo-and endo-type enzymes, wit h optimum pi-Is for their activities of 5.0 and 4.5. The thermostabili ty of amylase II was enhanced by calcium chloride, and the enzyme was stable when heated at 60 degrees C for 3 h. The activity of amylase I- b was not affected by calcium chloride, but was gradually reduced by h eating at 60 degrees C. The optimum temperatures of amylases I-b and I I were 65 and 70 degrees C (Ca2+), respectively.