Applied Microbiology and Biotechnology

, Volume 87, Issue 1, pp 225–233

Cloning, expression, and characterization of a thermostable glucoamylase from Thermoanaerobacter tengcongensis MB4

Authors

  • Yingying Zheng
    • State Key Laboratory of Microbial Resources, Institute of MicrobiologyChinese Academy of Sciences
    • The Graduate SchoolChinese Academy of Sciences
  • Yanfen Xue
    • State Key Laboratory of Microbial Resources, Institute of MicrobiologyChinese Academy of Sciences
  • Yueling Zhang
    • Tianjin Institute of Industrial BiotechnologyChinese Academy of Sciences
  • Cheng Zhou
    • State Key Laboratory of Microbial Resources, Institute of MicrobiologyChinese Academy of Sciences
    • Lehrstuhl für BiotechnologieRWTH Aachen University
    • State Key Laboratory of Microbial Resources, Institute of MicrobiologyChinese Academy of Sciences
Biotechnologically Relevant Enzymes and Proteins

DOI: 10.1007/s00253-010-2439-0

Cite this article as:
Zheng, Y., Xue, Y., Zhang, Y. et al. Appl Microbiol Biotechnol (2010) 87: 225. doi:10.1007/s00253-010-2439-0

Abstract

A thermostable glucoamylase (TtcGA) from Thermoanaerobacter tengcongensis MB4 was successfully expressed in Escherichia coli. The full-length gene (2112 bp) encodes a 703-amino acid polypeptide including a predicted signal peptide of 21 residues. The recombinant mature protein was partially purified to 30-fold homogeneity by heat treatment and gel filtration chromatography. The mature protein is a monomer with the molecular weight of 77 kD. The recombinant enzyme showed maximum activity at 75 °C and pH 5.0. It is the most thermostable bacterial glucoamylase described to date with nearly no activity loss after incubation at 75 °C for 6 h. TtcGA can hydrolyze both α-1, 4- and α-1, 6-glycosidic linkages in various α-glucans. It showed preference for maltooligosaccharides over polysaccharides with specific activity of 80 U/mg towards maltose. Kinetic studies revealed that TtcGA had the highest activity on maltooligosaccharide with four monosaccharide units. The cations Ca2+, Mn2+, Co2+, Mg2+, and reducing agent DTT showed no obvious effects on the action of TtcGA. In contrast, the enzyme was inactivated by Zn2+, Pb2+, Cu2+, and EDTA.

Keywords

GlucoamylaseThermoanaerobacter tengcongensisRecombinant expressionThermostable

Copyright information

© Springer-Verlag 2010