CEEPOx – Development of a system solution for chemo-electro-enzymatic peracid-mediated oxidation, exemplified through the production of chiral monoterpenes

The combination of electrochemistry and enzyme catalysis enables manifold forward-looking production systems and resource conserving processes.

In electroenzymatic processes, electrochemical reactions are used to produce reactants as well as to regenerate or substitute cosubstrates. Especially the combination of hydrogen peroxide-dependent enzymes (peroxidases, peroxygenases, laccases and under special conditions lipases and P450 monooxygenases) with electrochemical processes shows an extremely high application potential.

For example peroxidases can be used for several selective oxygen transfer reactions as hydroxylations or epoxidations. Due to a broad substrate- and reaction spectrum and the independence of cofactors, those enzymes are industrially interesting and versatilely applicable. Besides the application in synthesis, their reaction diversity provides the possibility to apply those enzymes in persistent pollutant removal, e.g. in waste water treatment.

However, most H₂O₂-dependent enzymes show low stability towards their cosubstrate. This is one of the main reasons, why to date, these enzymes are rarely used in industrial processes. The adjustable electrochemical H₂O₂-production can be used to drastically increase the total turnover number (ttn) of the reaction and enable high space time yields at the same time. By electrochemical adjustment of the H₂O₂-production rate, it is possible to keep the cosubstrate concentration below the critical value, nevertheless achieving high production rates.

In previous work, gas diffusion electrodes have shown to be the most suitable electrode type for electroenzymatic oxidations and oxygenations [1-4].

In this project, we will develop several system solutions for the application of H₂O₂-dependent enzymes using the examples of chloroperoxidase, unspecific peroxygenase and lipase.

1.            Getrey, L., et al., Enzymatic halogenation of the phenolic monoterpenes thymol and carvacrol with chloroperoxidase. Green Chemistry, 2014. 16(3): p. 1104-1108.

2.            Holtmann, D., et al., Electroenzymatic process to overcome enzyme instabilities. Catalysis Communications, 2014. 51(0): p. 82-85.

3.            Krieg, T., et al., Gas diffusion electrode as novel reaction system for an electro-enzymatic process with chloroperoxidase. Green Chemistry, 2011. 13(10): p. 2686-2689.

4.            Horst, A.E., K.M. Mangold, and D. Holtmann, Application of gas diffusion electrodes in bioelectrochemical syntheses and energy conversion. Biotechnology and Bioengineering, 2015.