Browsing by Author "Kiel, Martina"

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Open Access
Biotechnological production, isolation and characterisation of (2R,3S)‐2,3‐dihydroxy‐2,3‐dihydrobenzoate
(2025) Kiel, Martina; Barrantes, Israel; Pieper, Dietmar H.; Engesser, Karl‐Heinrich
Bacterial Rieske non‐heme iron oxygenases catalyse the transformation of a wide range of aromatic compounds to vicinal cis ‐dihydrodiols. Such compounds have been successfully applied in chemoenzymatic synthetic routes for, for example, pharmaceuticals, natural products and polymers. In the case of benzoate, only (1 S ,2 R )‐ cis ‐1,2‐dihydroxy‐2‐hydrobenzoate is readily accessible via enzymatic transformation, but not the regioisomeric cis ‐2,3‐dihydroxy‐2,3‐dihydrobenzoate (2,3‐DD) or cis ‐3,4‐dihydroxy‐3,4‐dihydrobenzoate. While trace amounts of putative cis ‐2,3‐DD have been obtained before by using p ‐cumate 2,3‐dioxygenase (PCDO) or a combination of chlorobenzene dioxygenase and nitrilase, none of these approaches enabled its production and isolation at a greater scale for potential use as a chiral building block in organic synthesis. We here provide a protocol for biotransformation of benzoate yielding (2 R ,3 S )‐2,3‐dihydroxy‐2,3‐dihydrobenzoate using the PCDO of Pseudomonas citronellolis strain EB200 with negligible formation of side products. An isolation procedure suitable for production of the 2,3‐DD sodium salt monohydrate at high purity (> 95%) at a gram scale, and a comprehensive characterisation of this novel metabolite is given.
Open Access
Plant uptake, translocation and metabolism of PBDEs in plants of food and feed industry : a review
(2020) Dobslaw, Daniel; Woiski, Christine; Kiel, Martina; Kuch, Bertram; Breuer, Jörn
Polybrominated diphenyl ethers (PBDEs) have widely been used for decades as flame retardants in a variety of products like plastics for building insulation, upholstered furniture, electrical appliances, vehicles, aircrafts, polyurethane foams, textiles, cable insulation, appliance plugs and various technical plastics in concentrations of 5-30%. However, PBDEs also act as endocrine disrupters, neurotoxins, and negatively affect fertility. In 2001, worldwide consumption of technically relevant penta-BDEs was still estimated at 7500 tons, octa-BDEs at 3790 tons, and deca-BDE at 56,100 tons, but 50-60% of this total volume are discharged into the environment via sewage sludge and its agricultural use alone. In addition, soils are ubiquitously contaminated by the gaseous or particle-bound transport of PBDEs, which today has its main source in highly contaminated electronic waste recycling sites. The emitted PBDEs enter the food chain via uptake by the plants’ roots and shoots. However, uptake and intrinsic transport behaviour strongly depend on crop specifics and various soil parameters. The relevant exposure and transformation pathways, transport-relevant soil and plant characteristics and both root concentration factors (RCF) and transfer factors (TF) as derivable parameters are addressed and quantified in this review. Finally, a simple predictive model for quantification of RCF and TF based on log KOW values and the organic content of the soil/lipid content of the plants is also presented.