title: Epoxide hydrolase activity of Streptomyces strains.
abstract: The discovery of epoxide hydrolases within a Streptomyces sp. strain collection is described. Screening was performed in 96 well microtiter plates using a modified 4-(p-nitrobenzyl)pyridine assay with styrene oxide, 1,2-epoxy-hexane or 3-phenyl ethylglycidate (3-PEG) as substrates. Out of 120 strains investigated, S. antibioticus Tü4, S. arenae Tü495 and S. fradiae Tü27 exhibited epoxide hydrolase activity. These strains were further investigated by performing laboratory-scale biotransformations utilizing styrene oxide, 1,2-epoxy-hexane and 3-PEG followed by subsequent quantitative analysis employing chiral gas chromatography. The highest conversions were achieved with whole cells from S. antibioticus Tü4 in the presence of 10% (v/v) DMSO. However, enantioselectivity was only satisfying (E = 31) in the presence of 5% (v/v) acetone, which allowed isolation of optically pure non-hydrolyzed (R)-styrene oxide (99% enantiomeric excess (ee)) and (S)-phenyl-1,2-ethandiol (72% ee) at 55% conversion after 24 h. The resolution of 3-PEG proceeded with slightly lower enantioselectivity albeit higher reaction rates. With S. fradiae Tü27 and S. arenae Tü495 enantioselectivity towards styrene oxide was only E = 3-4.
authors.affiliation: Institut für Technische Biochemie, Universität Stuttgart, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Zocher
authors.forename: M M
authors.initials: MM
authors.lastname: Enzelberger
authors.forename: U T
authors.initials: UT
authors.lastname: Bornscheuer
authors.forename: B
authors.initials: B
authors.lastname: Hauer
authors.forename: W
authors.initials: W
authors.lastname: Wohlleben
authors.forename: R D
authors.initials: RD
authors.lastname: Schmid
mesh_terms: D004851:Epoxide Hydrolases / Q000378:metabolism*; D004852:Epoxy Compounds / Q000378:metabolism; D013302:Streptomyces / Q000201:enzymology*
chemical_list: D004852:Epoxy Compounds; C013690:styrene oxide; D004851:Epoxide Hydrolases