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Enancjoselektywna redukcja wybranych α-aryloketonów w kulturach szczepów Coryneum betulinum KCh 6534 i Chaetomium sp. KCh 665

Janeczko T., Świzdor A., Chmolowska D., Dmochowska-Gładysz J., Kozłowska E., Dymarska M., Kostrzewa-Susłow E.

Przemysł Chemiczny

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2016

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T. 95, nr 8

1617--1621

PL

Przeprowadzono biotransformacje piętnastu substratów w kulturach dwóch szczepów grzybów strzępkowych: Coryneum betulinum KCh 6534 i Chaetomium sp. KCh 6651. Badane biokatalizatory charakteryzują się bardzo wysoką specyficznością substratową. Zaobserwowano wyraźny wpływ budowy zastosowanego substratu na stopień konwersji oraz enancjoselektywność procesu redukcji. W kulturze C. betulinum uzyskano enencjomerycznie czysty (S)-1-(1-naftylo)-etanol i (S)-1-(6-tetralino)-etanol. W kulturze szczepu z gatunku Chaetomium uzyskano z wysokim nadmiarem enancjomerycznym zarówno alkohole o konfiguracji absolutnej S: 1-(4-bromofenylo)-etanol i 1-cykloheksyloetanol, jak i R: 1-(4-metylofenylo)-etanol i 7-metoksy-1-tetralol.

EN

Fifteen α-aryloketones were biotransformed to resp. enantimerically pure EtOH or tetralol derivatives by using Coryneum betulinum KCh 6534 and Chaetomium sp. KCh 6651 strains of filamentous fungi. A very high substrate specificity and a significant impact of the substrate structure on the conversion and enantioselectivity of the redn. were obsd. In the culture of C. Betulinum, enantiomarically pure (S)-1-(1-naphthyl)-ethanol and (S)-1-(6-tetralino)-ethanol were obtained. On the contrary, both (S)-(1-(4-bromo- phenyl)-ethanol and 1-cyclohexylethanol) as well as (R)-(1-(4-methylphenyl)ethanol and (R)-7-methoxy-1-tetralol were produced in the culture of Chaetomium species in high enantiomeric excess.

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Enancjoselektywna redukcja pochodnych β-tetralonu w kulturze szczepów Coryneum betulinum KCh 6534 i Chaetomium sp. KCh 6651

Janeczko T., Świzdor A., Dmochowska-Gładysz J., Kozłowska E., Dymarska M., Kostrzewa-Susłow E.

Przemysł Chemiczny

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2016

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T. 95, nr 9

1737--1739

PL

Zbadano aktywność katalityczną dwóch szczepów Coryneum betulinum KCh 6534 i Chaetomium sp. KCh 6651 względem pochodnych β-tetralonu. Cztery pochodne (6-, 7- i 8-metoksy- oraz 6-chloro-β-tetralon) spośród pięciu zastosowanych ulegały efektywnej enancjoselektywnej redukcji do zgodnych z regułą Preloga S-alkoholi.

EN

Two of Coryneum betulinum KCh 6534 and Chaetomium sp. KCh 6651 strains were used for redn. of 6-, 7- and 8-methoxy-β-tetralones and 6-chloro-β-tetralone. An efficient enantioselective redn. resulted in formation of resp. tetralols consistently with the Prelog rule.

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Enzymatyczne reakcje rozszczepienia wiązania C–C : zastosowanie w syntezie związków zapachowych, farmaceutyków oraz w bioremediacji

Panek A., Milecka-Tronina N., Świzdor A.

Wiadomości Chemiczne

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2015

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[Z] 69, 5-6

337--368

EN

The microorganisms are able to utilize natural and synthetic compounds of broad structural diversity as a source of carbon and energy, converting these substrates into low molecular weight products (mainly H2O, CO2 and NH3). The main role in this metabolism is played by the enzymes that catalyze reactions of the C–C bond cleavage. Such reactions are the key step of the primary metabolism of fatty acids in eukaryotic cells by the β-oxidation. The enzymatic systems associated with the C–C bond cleavage have been applied in the synthesis of valuable natural products and in the bioremediation processes. Microbial transformations of natural compounds, in which the reactions of β-oxidation cycle are used, allow the formation of natural aromatic compounds (used as food additives), pharmaceuticals and ingredients of cosmetic compositions. Using this path one can obtain methyl ketones (e.g. responsible for the characteristic smell of cheeses), γ-lactones determining the scent of several popular fruits, and vanillin. A modification of the natural steroids: saponins, alkaloids, sterols, bile acids to products useful in the synthesis of steroid drugs is the most important area of use of the enzymatic C–C bond cleavage, due to the practical significance of the products. Enzymes that catalyze the C–C bonds cleavage are important in the process of biodegradation of toxic aromatic hydrocarbons and their derivatives (bioremediation).

4

Enzymatyczne utlenianie typu Baeyera-Villgera

Kołek T., Świzdor A., Panek A.

Wiadomości Chemiczne

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2009

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[Z] 63, 9-10

819-845

EN

Baeyer-Villiger (BV) reaction is oxidation of ketones, leading to cleavage of one of the C-CO-C bonds with simultaneous insertion of an oxygen atom into the cleaved bond. Resulting products obtained from cyclic ketones are lactones, while esters are obtained from acyclic ketones. Numerous strains of microorganisms produce enzymes catalyzing BV oxidation. These enzymes participate in the processes of degradation of natural and synthetic ketones, which can be used by the microorganisms as carbon source (Scheme 3 and 4). The enzymes are monooxygenases (Baeyer-Villigerases, BVMOs), usually containing flavinoadenine nucleotide and cooperating with NAD(P)H reductases. Research on the role of BV oxidation in degradation processes has evolved into intensive studies on the mechanism of this reaction and its use in synthesis, especially after isolation (in 1976) of cyclohexane monooxygenase from Acinetobacter sp. NCIB9871(CHMOAcineto 1) [9]. Subsequently, further strains were identified which produced BVMOs catalyzing oxidation of ketones of diverse structures. In addition to the best-characterized cyclohexane monooxygenase, there are: cyclopentanone, phenylacetone, cyclododecanone, aliphatic ketone and 2-oxo-3-en-4,5,5-trimethyl-cyclopentenylacetic acid monooxygenases. The adjective characterizing a given BVMO is derived from the ketone constituting carbon source, or from the ketone which is oxidized with the highest yield. In addition to these ketones, the enzymes accept their various structural analogues, therefore it is possible to select a biocatalyst which carries out oxidation of a given substrate. Among BVMOs, particularly selective are the enzymes carrying out BV oxidation of steroidal ketones: these enzymes operate only on steroid substrates, mostly containing 3-oxo--4-en moiety, but also they exhibit regioselectivity as well - the oxidation of ketones takes place only at C-17. During the regioselective enzymatic oxidation, "atypical" lactones [2, 4], which are not produced in chemical BV oxidation processes, are sometimes formed. Products of stereoselective enzymatic reactions are optically pure lactones and esters, which are starting points for further asymmetric synthesis of biologically active compounds, including medicines. The application of genetic engineering allows obtaining recombinant microbial strains, which are non-pathogenic and produce larger amounts of the enzyme than the wild-type strains. The recombinants are also able to produce mutated BVMOs exhibiting higher selectivity and/or lifetime, as well as activity towards different spectrum of substrates than the parent enzymes [2]. However, reaction yields of transformations carried out by the recombinants are still not significantly better than the results obtained with the wild-type strains. The recombinants usually require an expensive reagent, isopropyl-? --D-tiogalactopyranoside (ITPG), to induce their BVMOs [23]. Enzymatic BV oxidation, due to the selectivity of the enzymatic action, is competitive to the chemical oxidation. The enzyme selectivity allows for using pure products, including enantiopure compounds, with high yield. The process is environmentally friendly, because the oxidizer in the enzymatic BV reaction is molecular oxygen, and the amount of byproducts is limited. Synthetic application of BVMOs is limited by three principal factors: isolation of the enzyme in amounts suitable for large-scale applications, decrease in the enzymatic activity in the presence of the substrate and/or the product, and the isolation of the product. Separation of the unreacted enantiomer of the substrate in the process of kinetic separation of the racemic mixture, or separation of regioisomeric lactones are costly and time-consuming operations. Another possible problem is the fact that some strains producing useful BVMOs are pathogenic. Therefore, multidirectional research efforts are devoted to overcome the aforementioned barriers with the goal of establishing economically viable methods of biotransformations [4].

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Reakcje hydroksylacji z udziałem dehydrogenez : zastosowanie w syntezie

Kołek T., Świzdor A., Szpineter A.

Wiadomości Chemiczne

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2004

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[Z] 58, 3-4

245--262

EN

Although the majority of enzymatic hydroxylation reactions is catalysed by monooxygenases, dehydrogenases also play an important role in many reactions of this type. For example, dehydrogenases take part in hydroxylation of alifatic acids or nicotinic acid and its analogue. These reactions are important for degradation, biosynthesis and metabolism processes. Also, enzymic hydroxylation has been succesfully applied to the synthesis of L-carnitine, which is pharmacologically important compound. Another synthetic application involves enantioselective hydroxylation of isobutyric acid, where the proper catalyst species selection may lead to each enantiomer of the product selectively. Both enantiomers of b-hydroxyisobutyric acid are known as valuable chiral synthons for synthesis of many biologically active compounds, i.e. drugs, vitamins and others. The mechanism of alifatic compounds hydroxylation is well known - all the steps have been well documented. The reaction described were carried out by means of induced enzymes. The proof of dehydrogenases mediation in hydroxylation of N-heterocyclic substrates is the fact, that the oxygen in hydroxyl group derives from water, not from the air. Some of these reactions proceed quantitatively, affording very clean products. The reaction that found practical application of considerable importance is the hydroxylation of nicotinic acid (being precursor of a new generation insccticide) and its analogues. It is highly probable that the microbial hydroxylation of this type can find application in transformations of so called "enewable resource" (i.e. nicotine) in order to obtain important biologically active products.