Zinc hydroxide salts as new supports for the immobilization of Pseudomonas cepacia lipase

Abstract

Layered double hydroxides (LDHs) are brucite-like nanomaterials that have been used to immobilize several enzymes. However, layered hydroxide salts (LHSs), another group of brucite-like nanomaterials, have not yet been used for enzyme immobilization. In this work, we prepared two types of layered hydroxide salts, zinc hydroxide nitrate (ZHN: Zn₅(OH)₈(NO₃)₂^.2H₂O) and zinc hydroxide chloride (ZHC: Zn₅(OH)₈Cl₂^.H₂O) and used them to immobilize Pseudomonas cepacia lipase (LipPS). The best protein loading for both ZHN and ZHC was 162.5 mg g⁻¹ of LHS, which gave high values of triolein-hydrolyzing activity in organic medium (103 U g⁻¹ for LipPS-ZHN and 105 U g⁻¹ for LipPS-ZHC), immobilization efficiencies above 90% and activity retentions above 170%. In the kinetic resolution of (R,S)-1-phenylethanol, LipPS-ZHN gave better results, with 50% conversion being obtained in 2 h and an ee_s of 99%. With LipPS-ZHC, the conversion at 2 h was 40% and the ee_s, was lower, only 73%. For both immobilized materials, the ee_p was higher than 99% and E was higher than 200. The immobilized materials were stable after 5 cycles of reuse in successive 2-h kinetic resolutions. These results demonstrate that the layered hydroxide salts ZHN and ZHC have good potential as supports for the immobilization of lipases.

Keywords:

• Pseudomonas cepacia lipase
• immobilization
• layered hydroxide salts
• enzymatic kinetic resolution

Authors’ contributions

All authors contributed to the conception and design of the study. Material preparation, data collection and analysis were performed by Glauco Silva Dias. Nadia Krieger and Fernando Wypych directly supervised the work. The first draft of the manuscript was written by Glauco Silva Dias and all authors commented on this first draft and subsequent versions of the manuscript. All authors read and approved the final manuscript.

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Although funding was received from various research funding agencies (listed in the acknowledgements section), none of the funding agencies were involved in the design, execution or reporting of the work.

Additional information

Funding

This study was financed (Finance Code 001) by CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior), a Brazilian government agency for the development of personnel in higher education and by a project financed by the Brazilian-Argentine Biotechnology Center (CBAB/CABBIO) and administered by CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico), a Brazilian government agency for the advancement of science and technology (Project 441015/2016-6). Research scholarships were granted to Glauco Silva Dias by CAPES and to David Alexander Mitchell, Fernando Wypych and Nadia Krieger by CNPq. These funding agencies were not involved in the design, execution or reporting of the work.