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ARS Home » Midwest Area » Peoria, Illinois » National Center for Agricultural Utilization Research » Bioenergy Research » Research » Publications at this Location » Publication #303649
Title: A thermostable cyclodextrin glycosyltransferase from Thermoanaerobacter sp. 5K

Author
item AVCI, AYSE - Sakarya University
item Nichols, Nancy
item Saha, Badal
item Frazer, Sarah
item Cotta, Michael
item DONMEZ, SEDAT - Ankara University Of Turkey

Submitted to: Current Topics in Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/16/2014
Publication Date: 4/3/2015
Publication URL: http://handle.nal.usda.gov/10113/60685
Citation: Avci, A., Nichols, N.N., Saha, B.C., Frazer, S.E., Cotta, M.A., Donmez, S. 2015. A thermostable cyclodextrin glycosyltransferase from Thermoanaerobacter sp. 5K. Current Biotechnology. 3(4):305-312.

Interpretive Summary: This research describes a new enzyme for making cyclodextrins, solubilizing agents made from starch and widely used in several industries including pharmaceuticals, food, and cosmetics. The new enzyme is active at high temperatures and tolerates a wide pH range, making it suitable for industrial use. Two genes for this enzyme were identified, providing a resource for further genetic improvement of this group of enzymes. This research will be of interest to starch processors and to users of cyclodextrins.

Technical Abstract: Cyclodextrin glycosyltransferase (CGTase) from the thermophilic anaerobe Thermoanaerobacter sp. 5K was purified and characterized. The enzyme was purified with ammonium sulfate precipitation followed by a-CD-bound, epoxy-activated Sepharose 6B affinity chromatography. Molecular weight of the purified enzyme was 70.6 kDa. The enzyme had optimal activity at 80-90°C and retained greater than 90% activity between 75°C and 95°C. Optimal pH activity was observed at 7.0, with at least 50% activity between pH 4.0 and 9.0. It was highly stable at elevated temperature, with no loss of activity after incubation at 80°C for 4 hours or at 90°C for 30 min. Km and Vmax values were 0.222 mg/mL and 0.206 mg ß-CD/mL/min, respectively, with soluble starch. Amino acid composition of the enzyme was deduced from the sequence of the cloned CGTase gene. The mature enzyme has a deduced molecular weight of 75.63 kDa and contains residues conserved in the CGTase class of amylase enzymes.