Thermal Stability and Starch Degradation Profile of α-Amylase from Streptomyces avermitilis

• Published in: Bioscience, biotechnology, and biochemistry Vol. 77; no. 12; pp. 2449 - 2453
• Main Authors: HWANG, Sang Youn, NAKASHIMA, Kazunori, OKAI, Naoko, OKAZAKI, Fumiyoshi, MIYAKE, Michiru, HARAZONO, Koichi, OGINO, Chiaki, KONDO, Akihiko
• Format: Journal Article
• Language: English
• Published: England Japan Society for Bioscience, Biotechnology, and Agrochemistry 2013
• Subjects: alpha-Amylases - chemistry; alpha-Amylases - genetics; alpha-Amylases - metabolism; Ammonium sulfates; Amylases; calcium-dependent thermal stability; Chromatography; Degradation; Dichroism; Enzyme Stability; maltogenic α-amylase; Maltose; Maltose - biosynthesis; Metal ions; Metals - pharmacology; Protein Conformation; Starch - metabolism; Starches; Streptomyces; Streptomyces - enzymology; Streptomyces - genetics; Streptomyces avermitilis; Streptomyces lividans; Substrate Specificity - drug effects; Temperature; Thermal stability
• ISSN: 0916-8451; 1347-6947
• DOI: 10.1271/bbb.130556

Amylases from Streptomyces are useful in the production of maltooligosaccharides, but they have weak thermal stability at temperatures higher than 40 °C. In this study, α-amylase (SAV5981 gene of Streptomyces avermitilis) was expressed from Streptomyces lividans 1326 and purified by ammonium sulfate fractionation followed by anionic chromatography (Q-HP sepharose). The properties of the purified SAV5981 amylase were determined by the starch-iodine method. The effect of metal ions on amylase activity was investigated. The optimal temperature shifted from 25 to 50 °C with the addition of the Ca 2+ ion. The thermal stability of SAV5981 was also dramatically enhanced by the addition of 10 mM CaCl 2 . Improvement of the thermal stability of SAV5981 was examined by CD spectra in the presence and the absence of the Ca 2+ ion. Thin-layer chromatography (TLC) analysis and HPLC analysis of starch degradation revealed that SAV5981 mainly produced maltose and maltotriose, not glucose. The maltoorigosaccharide-producing amylase examined in this study has the potential in the industrial application of oligosaccharide production.