Characterization of a thermostable glycoside hydrolase (CMbg0408) from the hyperthermophilic archaeon Caldivirga maquilingensis IC-167

Publication Type

Journal contribution (peer reviewed)

Authors

Letsididi, R.; Hassanin, H.A.M.; Koko, M.Y.F.; Ndayishimiye, J.B.; Zhang, T.; Jiang, B.; Stressler, T.; Fischer, L.; Mu, W.

Year of publication

2016

Published in

Journal of the Science of Food and Agriculture

DOI

10.1002/jsfa.8019

BACKGROUND: Hyperthermophilic archaea capable of functioning optimally at very high temperatures are a good source for unique and industrially important thermostable enzymes.

RESULTS: A glycoside hydrolase (GH) family 1 β-galactosidase gene (BglB) from a hyperthermophilic archaeon Caldivirga maquilingensis IC-167 was cloned and expressed in Escherichia coli. The recombinant enzyme (CMbg0408) displayed optimum activity at 110 °C and pH 5.0. It also retained 92% and 70% of its maximal activity at 115 and 120 °C, respectively. The enzyme was completely thermostable and active after 120 min incubation at 80 and 90 °C. It also showed broad substrate specificity with activities of 8,876 ± 185 U mg-1 for p-nitrophenyl-β-D-galactopyranoside, 4,464 ± 172 U mg-1 for p-nitrophenyl-β-D-glucopyranoside, 1,486 ± 68 U mg-1 for o-nitrophenyl-β-D-galactopyranoside, 2,250 ± 86 U mg-1 for o-nitrophenyl-β-D-xylopyranoside, and 175 ± 4 U mg-1 for lactose. A catalytic efficiency (kcat/Km) of 3,059 ± 122 mM-1 s-1 and Km value of 8.1 ± 0.08 mM were displayed towards p-nitrophenyl-β-D-galactopyranoside.

CONCLUSION: Due to its remarkable thermostability and high activity at high temperatures, this novel β-galactosidase may be useful for food and pharmaceutical applications.