African Journal of
Microbiology Research

  • Abbreviation: Afr. J. Microbiol. Res.
  • Language: English
  • ISSN: 1996-0808
  • DOI: 10.5897/AJMR
  • Start Year: 2007
  • Published Articles: 5232

Full Length Research Paper

Isolation and characterization of a cold-active amylase from marine Wangia sp. C52

Jianguo Liu1*, Zhiqiang Zhang1, Hongyue Dang1, Jianren Lu2 and Zhanfeng Cui3
  1Center for Bioengineering and Biotechnology, China University of Petroleum (East China), Qingdao 266555, People’s Republic of China. 2School of Physics, Manchester University, Manchester M60 1QD, UK. 3Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, UK.
Email: [email protected]

  •  Accepted: 07 April 2011
  •  Published: 18 May 2011

Abstract

 

Amylase activity was detected in the culture medium of marine Wangia sp. C52, which was isolated from the Southern Okinawa Trough deep-sea sediment. In the present study, a cold-active amylase was purified to homogeneity from the culture broth by ammonium sulfate precipitation and gel filtration chromatography. The molecular mass of the amyalse was 58 kDa, and its isoelectric point was close to 5.6. The optimal pH and temperature were 30°C and 6.0, respectively. In the presence of Ca2+ and Co2+, the enzyme activity was stimulated while Cu2+, Hg2+, Mn2+, Zn2+, Fe3+, Al3+, EDTA, EGTA and SDS reduced the activity. Km and Vmax values of the purified enzyme for soluble starch were 2.08 ± 0.3 mg/ml and 1.26 ± 0.02 mg/ml/min, respectively. The final purified enzyme had α-helix of 25%, β-sheet of 26% and random coil of 49%, consistent with the theoretical values. This showed that the purified amylase folded with a reasonable secondary structure.

 

Key words: Cold-active amylase, Wangia sp., purification, enzyme characterization.