Applied Microbiology and Biotechnology

, Volume 80, Issue 4, pp 615–625

Identification of two novel esterases from a marine metagenomic library derived from South China Sea

Biotechnologically Relevant Enzymes and Proteins

DOI: 10.1007/s00253-008-1566-3

Cite this article as:
Chu, X., He, H., Guo, C. et al. Appl Microbiol Biotechnol (2008) 80: 615. doi:10.1007/s00253-008-1566-3

Abstract

The demand for novel biocatalysts is increasing in modern biotechnology, which greatly stimulates the development of powerful tools to explore the genetic resources in the environment. Metagenomics, a culture independent strategy, provides an access to valuable genetic resources of the uncultured microbes. In this study, two novel esterase genes designated as estA and estB, which encoded 277- and 328-amino-acid peptides, respectively, were isolated from a marine microbial metagenomic library by functional screening, and the corresponding esterases EstA and EstB were biochemically characterized. Amino acid sequence comparison and phylogenetic analysis indicated that EstA together with other putative lipolytic enzymes was closely related to family III, and EstB with its relatives formed a subfamily of family IV. Site-directed mutagenesis showed that EstA contained classical catalytic triad made up of S146–D222–H255, whereas EstB contained an unusual catalytic triad which consisted of S–E–H, an important feature of the subfamily. EstA exhibited habitat-specific characteristics such as its high level of stability in the presence of various divalent cations and at high concentrations of NaCl. EstB displayed remarkable activity against p-nitrophenyl esters and was highly stable in 30% methanol, ethanol, dimethylformamide, and dimethyl sulfoxide, making EstB a potential candidate for industrial applications.

Keywords

Metagenome Esterase BAC library Phylogenetic tree Marine 

Copyright information

© Springer-Verlag 2008

Authors and Affiliations

  • Xinmin Chu
    • 1
  • Haoze He
    • 1
  • Changquan Guo
    • 1
  • Baolin Sun
    • 1
  1. 1.Hefei National Laboratory for Physical Sciences at Microscale and School of Life SciencesUniversity of Science and Technology of ChinaHefeiChina