Browsing by Author "Schelle, Jona T."

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Open Access
Enhanced semi‐preparative biotransformation of cumene dioxygenase : from analytical scale to product isolation
(2023) Schelle, Jona T.; Lepoittevin, William; Hauer, Bernhard
Scale‐up of oxygenase catalyzed reactions is often challenging due to the limited oxygen mass transfer in aqueous solutions. To overcome such limitation, we studied different scale‐up conditions using recombinant resting cells of E. coli JM109(DE3), harboring the cumene dioxygenase of Pseudomonas fluorescens IP01, for the dihydroxylation of naphthalene to (1R,2S)‐cis‐1,2‐dihydro‐1,2‐naphthalenediol. Thereby, vigorous stirring of the biotransformation in a 2 L round bottom flask in combination with an oxygen‐enriched headspace exhibited outstanding product formation after 1 h. Furthermore, the enhanced setup was used for the cumene dioxygenase catalyzed biosynthesis of 240 mg of valuable (+)‐trans‐carveol from (R)‐(+)‐limonene, demonstrating the application of our workflow for volatile compounds.
Open Access
Semi‐rational engineering of toluene dioxygenase from Pseudomonas putida F1 towards oxyfunctionalization of bicyclic aromatics
(2021) Wissner, Julian L.; Schelle, Jona T.; Escobedo‐Hinojosa, Wendy; Vogel, Andreas; Hauer, Bernhard
Toluene dioxygenase (TDO) from Pseudomonas putida F1 was engineered towards the oxyfunctionalization of bicyclic substrates. Single and double mutant libraries addressing 27 different positions, located at the active site and entrance channel were generated. In total, 176 different variants were tested employing the substrates naphthalene, 1,2,3,4‐tetrahydroquinoline, and 2‐phenylpyridine. Introduced mutations in positions M220, A223 and F366, exhibited major influences in terms of product formation, chemo‐, regio‐ and enantioselectivity. By semi‐rational evolution, we lighted up the TDO capability to convert bulkier substrates than its natural substrate, at unprecedented reported conversions. Thus, the most active TDO variants were applied to biocatalytic oxyfunctionalizations of 1,2,3,4‐tetrahydroquinoline, and 2‐phenylpyridine, enabling the production of substantial amounts of (+)‐(R)‐1,2,3,4‐tetrahydroquinoline‐4‐ol (71% isolated yield, 94% ee) and (+)‐(1S,2R)‐3‐(pyridin‐2‐yl)cyclohexa‐3,5‐diene‐1,2‐diol (60% isolated yield, 98% ee), respectively. Here, we provide a set of novel TDO‐based biocatalysts useful for the preparation of oxyfunctionalized bicyclic scaffolds, which are valuable to perform downstream synthetic processes.