title: Exploiting racemases.
abstract: Chiral resolutions of racemic mixtures are limited to a theoretical yield of 50 %. This yield can be doubled by integration of a step-wise or continuous racemization of the non-desired enantiomer. Many of the different routes along which the racemization step can be conducted require harsh treatments and are therefore often incompatible with the highly functionalized state of many compounds relevant for the life science industries. Employing enzymatic catalysis for racemization can therefore be highly beneficial. Racemases allow racemization in one reaction step. Most representatives from this group are found in the domain of amino acid or amino acid derivative racemization, with few other examples, notably the racemization of mandelic acid. Corresponding to the importance of enantiospecific conversion of amino acid precursor racemates for the production of enantiopure amino acids, the most important biotechnological use for racemases is the racemization of such precursors. However, alternative uses, in particular for mandelate and amino acid racemases, are emerging. Here, we summarize the natural roles of racemases and their occurrence, the applications, and the biochemistry and engineering of this promising class of biocatalysts.
authors.affiliation: ETH Zurich, Department of Biosystems Science and Engineering, Mattenstrasse 26, 4058, Basel, Switzerland.
authors.forename: Christian
authors.identifier: http://orcid.org/0000-0002-8526-8131
authors.initials: C
authors.lastname: Femmer
authors.affiliation: ETH Zurich, Department of Biosystems Science and Engineering, Mattenstrasse 26, 4058, Basel, Switzerland.
authors.forename: Matthias
authors.initials: M
authors.lastname: Bechtold
authors.affiliation: ETH Zurich, Department of Biosystems Science and Engineering, Mattenstrasse 26, 4058, Basel, Switzerland.
authors.forename: Tania Michelle
authors.initials: TM
authors.lastname: Roberts
authors.affiliation: ETH Zurich, Department of Biosystems Science and Engineering, Mattenstrasse 26, 4058, Basel, Switzerland. sven.panke@bsse.ethz.ch.
authors.forename: Sven
authors.initials: S
authors.lastname: Panke
mesh_terms: D000591:Amino Acid Isomerases / Q000378:metabolism*; D000596:Amino Acids / Q000378:metabolism*; D001419:Bacteria / Q000201:enzymology* / Q000378:metabolism*; D055162:Biocatalysis; D001709:Biotechnology; D008333:Mandelic Acids / Q000378:metabolism; D013237:Stereoisomerism
chemical_list: D000596:Amino Acids; D008333:Mandelic Acids; D000591:Amino Acid Isomerases; C037938:mandelic acid
keywords: Amino acids; Dynamic kinetic resolution; Enantiomers; Integrated processes; Racemases