ORIGINAL RESEARCH article
Front. Microbiol.
Sec. Extreme Microbiology
Volume 16 - 2025 | doi: 10.3389/fmicb.2025.1662394
This article is part of the Research TopicMicrobial Diversity and Survival Strategies in Polar EnvironmentsView all articles
Expression and Characterization of Est2: A Novel Cold-Adapted Esterase from Antarctic Bacterium Defining the New Esterase Family XXII
Provisionally accepted
- 1Qilu University of Technology, Jinan, China
- 2Shandong University, Qingdao, China
- 3Central South University, Changsha, China
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Extremozymes from Antarctic microbiota represent a potential source of unique biocatalysts. In this study, a novel esterase gene est2 was identified from the Antarctic bacterium Pseudomonas sp. A6-5. Phylogenetic and sequence analyses classified it as the founding member of a new esterase family XXII. The catalytic triad of the enzyme consisted of Ser141, Asp275, and His303, with the nucleophilic Ser141 situated within the characteristic GXSXG motif of α/β-hydrolases. Est2 exhibited remarkable cold-adaptation where 20 - 85% of the maximum activity was observed at temperatures ranging from 0-15℃. Substrate specificity profiling revealed preferential hydrolysis of medium-chain p-nitrophenyl esters and triglyceride emulsions. Enzyme activity was sensitive to inhibition by transition metals (1 mM of Mn2+, Cu2+, Co2+, Ni2+ or Zn2+), but alkali metals were considerably less effective. Representative polar-protic and -aprotic solvents uniformly inhibited Est2 activity. Collectively, these results suggest the structural stability of Est2 is largely governed by hydrophobic interactions and H-bonding, rather than ionic forces. Est2 appears to represent a unique cold-adaptive enzyme that may be suitable for bio-catalyzed environmental remediation.
Keywords: Antarctic, Bacteria, esterase, Cold-adapted, new esterase family XXII
Received: 09 Jul 2025; Accepted: 25 Aug 2025.
Copyright: © 2025 He, Sun, Zhang, Xing, He, Bielicki and Zhou. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Mingyang Zhou, Qilu University of Technology, Jinan, China
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