Engineering surface hydrophobicity improves activity of Bacillus thermocatenulatus lipase 2 enzyme

Ting Tang, Chongli Yuan, Hyun Tae Hwang, Xuebing Zhao, Doraiswami Ramkrishna, Dehua Liu, Arvind Varma

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

Bacillus thermocatenulatus lipase 2 (BTL2) is a promising industrial enzyme used in biodiesel production. Although BTL2 has high thermostability and good resistance to organic solvents, the activity of BTL2 is suboptimal for industrial processes. To improve BTL2 activity, we engineered BTL2 lipase by modulating hydrophobicity of its lid domain. Through site-directed mutagenesis, we constructed three mutants, namely Y225F+S232A, S232A+T236V and Q185L, to cover all uncharged hydrophilic amino acids within the lid domain. Activities of these mutants were characterized. Our findings suggest that one mutant (Y225F+S232A) showed ~35% activity increase in catalyzing heterogeneous hydrolytic reactions relevant for industrial applications. A mathematical framework was established to account for different molecular events that contribute to the observed apparent catalytic activities. Increases in hydrophobicity of lid domains were associated with increased interfacial adsorption of lipases and lower molecular enzymatic activities. The measured apparent activities of lipases include contributions from both events. Lid hydrophobicity can thus result in different changes in lipase activities depending on the mutation site. Our work demonstrates the feasibility of increasing BTL2 activity by modulating the hydrophobicity of lid domains and provides some guidelines for further improving BTL2 activity.

Original languageEnglish
Pages (from-to)1762-1769
Number of pages8
JournalBiotechnology Journal
Volume10
Issue number11
DOIs
StatePublished - Nov 2015

Bibliographical note

Publisher Copyright:
© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Keywords

  • Bacillus thermocatenulatus lipase 2 (BTL2)
  • Heterogeneous reaction
  • Hydrophobicity
  • Interfacial adsorption
  • Lid

ASJC Scopus subject areas

  • Applied Microbiology and Biotechnology
  • Molecular Medicine

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