Asymmetric syntheses with new oxidoreductases from cyanobacteria

Kathrin Hölsch, doctoral thesis Technische Universität München, 2009

Chiral alcohols constitute important intermediates in the synthesis of optically active compounds. These building blocks can be easily obtained by biocatalytic reduction of prochiral ketones. The discovery of a novel oxidoreductase in cyanobacteria capable of enantioselective reduction of even multi-halogenated ketones offers an alternative route to chiral building blocks. In this thesis, it was demonstrated that ketoacyl reductases from cyanobacteria are well suited for industrial processes in terms of specific activity, substrate spectrum and stability. A study of 16 ketoacyl reductases from cyanobacteria belonging to different taxonomic groups revealed enzymes with high potential for use in asymmetric synthesis of chiral alcohols. Exemplarily, a novel method for in situ regeneration of cofactors was elaborated and applied to asymmetric syntheses using one of those enzymes.


  • Hölsch K, Weuster-Botz D (2011): Kinetic mechanism of 3-ketoacyl-(acyl-carrier-protein) reductase from Synechococcus sp. strain PCC 7942: A useful enzyme for the production of chiral alcohols. J Mol Cat B: Enz 69: 89-94.
  • Hölsch K, Weuster-Botz D (2010): Enantioselective reduction of prochiral ketones by engineered bifunctional fusion proteins. Biotechnol Appl Biochem 56: 131-140.
  • Hölsch K, Weuster-Botz D (2010): New oxidoreductases from cyanobacteria: exploring nature’s diversity. Enz Microbial Technol 47: 228-235.
  • Gadler P, Reiter T, Hölsch K, Weuster-Botz D, Faber K (2009): Enantiocomplementary inverting sec-alkylsulfatase activity in cyano- and thio-bacteria Synechococcus and Paracoccus spp.: selectivity enhancement by medium engineering. Tetrahedron: Asymmetry 20: 115-118.
  • Hölsch K, Havel J, Haslbeck M, Weuster-Botz D (2008): Identification, cloning and characterization of a novel ketoreductase from the cyanobacterium Synechococcus sp. strain PCC 7942. Appl Environ Microbiol 74: 6697-6702.