Role of Two α- l-arabinofuranosidases in arabinoxylan degradation and characteristics of the encoding genes from shochu koji molds, Aspergillus kawachii and Aspergillus awamori

• Published in: Journal of bioscience and bioengineering Vol. 96; no. 3; pp. 232 - 241
• Main Authors: Koseki, Takuya, Okuda, Masaki, Sudoh, Shigetoshi, Kizaki, Yasuzo, Iwano, Kimio, Aramaki, Isao, Matsuzawa, Hiroshi
• Format: Journal Article
• Language: English
• Published: Amsterdarm Elsevier B.V 2003; Elsevier Science
• Subjects: AkabfA protein; AkabjB protein; alpha -L-Arabinofuranosidase; AMINO ACIDS; arabinoxylan; ASPERGILLUS; ASPERGILLUS AWAMORI; Aspergillus awamori shochu brewing; Aspergillus kawachii; AwabfA protein; AwabjB protein; BIODEGRADATION; Biological and medical sciences; Biotechnology; CELL WALLS; feruloyl esterase; Fundamental and applied biological sciences. Psychology; GENES; GLYCOSIDASES; plant cell-wall; XYLANS; α- l-arabinofuranosidase; α- l-arabinofuranosidase; plant cell-wall; Aspergillus kawachii; Aspergillus awamori shochu brewing; Biodegradation; Vegetals; Enzyme; α-L-arabino furanosidase; Brewing; α-L-Arabinofuranosidase; Cell wall; Fungi; Gene; Glycosidases; Hydrolases; Fungi Imperfecti; O-Glycosidases; shochu brewing; Thallophyta; Aspergillus awamori
• ISSN: 1389-1723; 1347-4421
• DOI: 10.1016/S1389-1723(03)80187-1

Two different α-
l-arabinofuranosidases from
Aspergillus kawachii were purified and characterized. The two enzymes acted synergically with xylanase in the degradation of arabinoxylan and resulted in an increase in the amount of ferulic acid release by feruloyl esterase. Both enzymes were acidophilic and acid stable enzymes which had an optimum pH of 4.0 and were stable at pH 3.0–7.0. The general properties of the enzymes including pH optima and pH stability were similar to those of
Aspergillus awamori. These results suggest that the α-
l-arabinofuranosidases contribute to an increase in cereal utilization and formation of aroma in shochu brewing. Two different genes encoding α-
l-arabinofuranosidases from
A. kawachii, designated as
AkabfA and
AkabjB, and those from
A. awamori, designated as
AwabfA and
AwabjB, were also cloned and characterized. The difference between the sequences of
AkabfA and
AwabfA was only one nucleotide, resulting in an amino acid difference in the sequence, and the enzymes were assigned to family 51 of glycoside hydrolases. On the other hand, the differences between the sequences of
AkabjB and
AwabjB and between their encoding proteins were two nucleotides and one amino acid residue, respectively, and the enzymes were assigned to family 54 of glycoside hydrolases. On comparison of the
abfA and
abjB genes among
A. kawachii, A. awamori, and
A. niger, the relationship between the two genes for
A. kawachii and
A. awamori was much closer than those between
A. niger and the others. Northern analyses showed that transcription of
AkabfB was greater than that of
AkabfA in the presence of
l-arabitol and
l-arabinose, and that transcriptions of both genes were not induced in the presence of sucrose and glucose.