Immobilization and characterization of a new regioselective and enantioselective lipase obtained from a metagenomic library

PLoS One. 2015 Feb 23;10(2):e0114945. doi: 10.1371/journal.pone.0114945. eCollection 2015.

Abstract

In previous work, a new lipase and its cognate foldase were identified and isolated from a metagenomic library constructed from soil samples contaminated with fat. This new lipase, called LipG9, is a true lipase that shows specific activities that are comparable to those of well-known industrially-used lipases with high activity against long-chain triglycerides. In the present work, LipG9 was co-expressed and co-immobilized with its foldase, on an inert hydrophobic support (Accurel MP1000). We studied the performance of this immobilized LipG9 (Im-LipG9) in organic media, in order to evaluate its potential for use in biocatalysis. Im-LipG9 showed good stability, maintaining a residual activity of more than 70% at 50 °C after incubation in n-heptane (log P 4.0) for 8 h. It was also stable in polar organic solvents such as ethanol (log P -0.23) and acetone (log P -0.31), maintaining more than 80% of its original activity after 8 h incubation at 30 °C. The synthesis of ethyl esters was tested with fatty acids of different chain lengths in n-heptane at 30 °C. The best conversions (90% in 3 h) were obtained for medium and long chain saturated fatty acids (C8, C14 and C16), with the maximum specific activity, 29 U per gram of immobilized preparation, being obtained with palmitic acid (C16). Im-LipG9 was sn-1,3-specific. In the transesterification of the alcohol (R,S)-1-phenylethanol with vinyl acetate and the hydrolysis of the analogous ester, (R,S)-1-phenylethyl acetate, Im-LipG9 showed excellent enantioselectivity for the R-isomer of both substrates (E> 200), giving an enantiomeric excess (ee) of higher than 95% for the products at 49% conversion. The results obtained in this work provide the basis for the development of applications of LipG9 in biocatalysis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / chemistry*
  • Bacterial Proteins / genetics
  • Biocatalysis
  • Enzymes, Immobilized / chemistry*
  • Enzymes, Immobilized / genetics
  • Esters
  • Fatty Acids / chemistry
  • Lipase / chemistry*
  • Lipase / genetics
  • Metagenome

Substances

  • Bacterial Proteins
  • Enzymes, Immobilized
  • Esters
  • Fatty Acids
  • Lipase
  • lipase foldase

Grants and funding

The work was supported by the following: Brazilian National Council for Scientific and Technological Development (CNPq) http://www.cnpq.br/; funding and research scholarships: NK EMS FOP DAM VPM AG MMS; Pronex/Fundação Araucária (Funding)(www.fappr.pr.gov.br/) EMS FOP; and Coordination for the Development of Higher Education Personnel (CAPES): research scholaships: RCA ACS. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.