Properties of cellulose-degrading enzymes from Aspergillus oryzae and their contribution to material utilization and alcohol yield in sake mash fermentation.
Four cellulose-degrading enzymes were identified in a solid-state culture of Aspergillus oryzae. The three major enzymes were purified and named Cel-1, Cel-2, and Cel-3, respectively. The molecular weights were determined to be 62, 120, and 34 kDa, respectively. The optimum temperature of Cel-3 activity was higher than that of the other enzymes. An acidic pH was found to be more suitable for Cel-1 activity than for the other enzymes, and Cel-3 was more stable under acidic conditions than the other two. These properties and the results of a protein homology search for N-terminal amino acid sequences suggest that Cel-1 and Cel-3 correspond to the previously isolated endo-1,4-beta-glucanase CelB and CelA, respectively. The analysis of substrate specificity suggested that Cel-2 is likely to be beta-glucosidase. The effect of Cel-1, Cel-2, and Cel-3 on the sake mash fermentation was determined and it was found that Cel-2 markedly improved material utilization and alcohol yield in sake mash fermentation.
Yamane
Yu-Ichi
Y
National Research Institute of Brewing, 3-7-1 Kagamiyama, Higashi-Hiroshima 739-0046, Japan. yamaney@nrib.go.jp
Fujita
Jin
J
Izuwa
Shinya
S
Fukuchi
Kaoru
K
Shimizu
Ryu-Ichi
R
Hiyoshi
Akira
A
Fukuda
Hisashi
H
Mikami
Shigeaki
S
Kizaki
Yasuzo
Y
Wakabayashi
Saburo
S