Halofrax volcanii as immobilised whole cell biocatalyst: new applications for halophilic systems

Haque, R.U.; Paradisi, F.; Allers, T.

Abstract

Enzyme-mediated synthesis of pharmaceutical compounds is a ‘green’ alternative to traditional synthetic chemistry, and microbial engineering opens up the possibility of using whole cells as mini-factories. Whole-cell biocatalysis reduces cost by eliminating expensive enzyme purification and cofactor addition steps, as well as resulting in increased enzyme stability. Haloferax volcanii is a model halophilic archaeon encoding highly salt and organic solvent tolerant enzymes such as alcohol dehydrogenase (HvADH2), which catalyses the reduction of aldehydes and ketone in the presence of NADPH/NADH cofactor. A H. volcanii strain for constitutive HvADH2 expression was generated using a strong synthetic promoter (p.syn). The strain was immobilised in calcium alginate beads and repeatedly used as a whole-cell biocatalyst. The reduction of acetophenone, used as test substrate, was very successful and high yields were detected from immobilised whole cells over repeated biotransformation cycles. The immobilised H. volcanii retained stability and high product yields after 1 month of storage at room temperature. This newly developed system offers halophilic enzyme expression in its native environment, high product yield, stability and reusability without the addition of any expensive NADPH/NADH cofactor. This is the first report of whole cell–mediated biocatalysis by the halophilic archaeon H. volcanii.

Citation

Haque, R., Paradisi, F., & Allers, T. (2019). Halofrax volcanii as immobilised whole cell biocatalyst: new applications for halophilic systems. Applied Microbiology and Biotechnology, 103(9), 3807-3817. https://doi.org/10.1007/s00253-019-09725-y

• Journal Article Type: Article
• Acceptance Date: Feb 24, 2019
• Online Publication Date: Mar 15, 2019
• Publication Date: 2019-05
• Deposit Date: Mar 6, 2019
• Publicly Available Date: Mar 16, 2020
• Journal: Applied Microbiology and Biotechnology
• Print ISSN: 0175-7598
• Electronic ISSN: 1432-0614
• Publisher: Springer Verlag
• Peer Reviewed: Peer Reviewed
• Volume: 103
• Issue: 9
• Pages: 3807-3817
• DOI: https://doi.org/10.1007/s00253-019-09725-y
• Keywords: Haloferax volcanii; Biocatalysis; Biotransformation; Whole cell immobilisation; Biocatalyst
• Public URL: https://nottingham-repository.worktribe.com/output/1611465
• Publisher URL: https://link.springer.com/article/10.1007%2Fs00253-019-09725-y