Recombinant Expression and Functional Analysis of GH2 β-Galactosidases Derived from Lactobacillus delbrueckii subsp. bulgaricus NSP1 and Streptococcus thermophilus RB16
- 1“National Center for Biotechnology” Ltd., 13/5 Korgalzhyn Road, Astana 010000, Kazakhstan
- 2Department of General Biology and Genomics, Institute of Natural Sciences, L.N. Gumilyov Eurasian National University, 2 Kanysh Satpayev Street, Astana 010008, Kazakhstan
- 3“GenLab” Ltd., 19/1 Malik Gabdullin Street, Astana 010000, Kazakhstan
Abstract
GH2 β-galactosidases are important industrial biocatalysts for lactose hydrolysis and prebiotic galacto-oligosaccharide (GOS) synthesis. Here, lacZ genes from Streptococcus thermophilus RB16 (StLacZ) and Lactobacillus delbrueckii subsp. bulgaricus NSP1 (LbLacZ) were cloned, sequenced and deposited in GenBank under accession numbers QB046854 and QB046855, respectively, and expressed in Escherichia coli BL21 (DE3). A comparative study was conducted to determine their catalytic activity. rLbLacZ was found to be a typical mesophilic enzyme, with the optimal pH of 6.5 and a temperature of 40 °C, and high apparent affinity for lactose (Km = 14.02 mM). Nevertheless, rStLacZ exhibited an alkaline optimum and high thermo-activity, with optimal catalytic rates at pH 9.0 and 55–60 °C, as well as a high turnover number (kcat = 128.82 s−1) and specific activity (63.5 U/mg) for lactose. Despite different functional substrate affinities and reaction rates, both enzymes proved to have similar overall catalytic efficiency. The enzymes required specific divalent metals and monovalent metal salts to achieve peak catalytic activity. rStLacZ catalyzes the rapid and early synthesis of fast-migrating transglycosylation intermediates, while rLbLacZ catalyzes the progressive formation of slower-migrating, more complex oligosaccharide fractions. These findings demonstrate the complementary industrial potential of rStLacZ for rapid bioprocesses at elevated temperatures and rLbLacZ for the gentle processing of dairy products.
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BibTeX
@article{shamsiyeva2026recombinant,
title = {{Recombinant Expression and Functional Analysis of GH2 β-Galactosidases Derived from Lactobacillus delbrueckii subsp. bulgaricus NSP1 and Streptococcus thermophilus RB16}},
author = {Yuliya Shamsiyeva and Anel Kostanova and Annelya Tursunbekova and Bekbolat Khassenov and Zhiger Akishev},
journal = {International Journal of Molecular Sciences},
year = {2026},
month = oct,
doi = {10.3390/ijms27209104},
url = {https://www.mdpi.com/1422-0067/27/20/9104},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Recombinant Expression and Functional Analysis of GH2 β-Galactosidases Derived from Lactobacillus delbrueckii subsp. bulgaricus NSP1 and Streptococcus thermophilus RB16
AU - Yuliya Shamsiyeva
AU - Anel Kostanova
AU - Annelya Tursunbekova
AU - Bekbolat Khassenov
AU - Zhiger Akishev
PY - 2026
DA - 2026/10/01
JO - International Journal of Molecular Sciences
DO - 10.3390/ijms27209104
UR - https://www.mdpi.com/1422-0067/27/20/9104
AB - GH2 β-galactosidases are important industrial biocatalysts for lactose hydrolysis and prebiotic galacto-oligosaccharide (GOS) synthesis. Here, lacZ genes from Streptococcus thermophilus RB16 (StLacZ) and Lactobacillus delbrueckii subsp. bulgaricus NSP1 (LbLacZ) were cloned, sequenced and deposited in GenBank under accession numbers QB046854 and QB046855, respectively, and expressed in Escherichia coli BL21 (DE3). A comparative study was conducted to determine their catalytic activity. rLbLacZ was found to be a typical mesophilic enzyme, with the optimal pH of 6.5 and a temperature of 40 °C, and high apparent affinity for lactose (Km = 14.02 mM). Nevertheless, rStLacZ exhibited an alkaline optimum and high thermo-activity, with optimal catalytic rates at pH 9.0 and 55–60 °C, as well as a high turnover number (kcat = 128.82 s−1) and specific activity (63.5 U/mg) for lactose. Despite different functional substrate affinities and reaction rates, both enzymes proved to have similar overall catalytic efficiency. The enzymes required specific divalent metals and monovalent metal salts to achieve peak catalytic activity. rStLacZ catalyzes the rapid and early synthesis of fast-migrating transglycosylation intermediates, while rLbLacZ catalyzes the progressive formation of slower-migrating, more complex oligosaccharide fractions. These findings demonstrate the complementary industrial potential of rStLacZ for rapid bioprocesses at elevated temperatures and rLbLacZ for the gentle processing of dairy products.
SN - 1422-0067
ER -