Tatyana S. Zhuk

Fruiting bodies of Mycetinisscorodonius, a mushroom with an intense garlic flavor, were cultivated under laboratory conditions. Focusing on sulfur compounds, volatile organic compounds of the freeze-dried fruiting bodies were analyzed for the first time by means of headspace solid-phase micro extraction and GC-MS/MS-olfactometry. Nine sulfur compounds were identified, including primarily methanethiol, methyl dithioformate, 2,3,5-trithiahexane, dimethyl trithiocarbonate and 2,4,5,7-tetrathiaoctane. For the first time, methyl dithioformate was detected in Mycetinis species. Only four aroma compounds were found in a dichloromethane extract, which were also quantitated. The quantitation ranged from 631 to 1699 mg/kg dry matter. For comparison, the garlic-scented plant Tulbaghia violacea was extracted due to the presence of the thiosulfinate marasmicin. Measurements of liquid Mycetinis and T. violacea extracts by UHPLC-MS and GC-MS/MS-O indicated the presence of the aroma precursor marasmicin in the fungal extract. GC-MS/MS measurements of a pure HPLC marasmicin fraction revealed the thermal degradation products of marasmicin.

The CH‐oxidative activity of Wolfiporia cocos cultures of different ages was studied utilizing diamondoid derivatives as conformationally rigid models. Adamantane‐1‐ol and 1‐bromoadamantane, traditional precursors for the synthesis of polysubstituted adamantanes, gave qualitatively similar reaction mixtures in which adamantane diols dominated. While the reactions occurred with high preparative yields, the biotransformation does not display clear differences from classic electrophilic or radical adamantane functionalization reactions. In contrast, the fungal oxidation of diamantane‐4‐ol occurred with unexpected selectivity yielding diamantane‐4,9‐diol and diamantane‐1,9‐diol. The latter product is quite uncharacteristic for diamantane chemistry because the most deactivated CH‐position is attacked. To elucidate the active fungal component, additional experiments were performed with supernatant and resting cells harvested at various culture ages. Oxidative activity was detected in resting cells from 4‐ and 6‐day‐old cultures in pure water medium, and from 6‐day‐old cultures in buffer at pH 2, but disappeared at higher pH values.

The biocatalytic aerobic production of ( E )‐2‐allylic aldehydes from their corresponding alcohols using lyophilisates of the basidiomycetous fungus Bjerkandera adusta is reported. The addition of small amounts of organic solvents to the reaction media increased the reaction and substrate conversion rates, allowing for to produce ( E )‐aldehydes under sustainable conditions. Citral (mixture of ( E )‐ and ( Z )‐3,7‐dimethylocta‐2,6‐dienal) was found as a result of the oxidation of geraniol (( E )‐3,7‐dimethyl‐2,6‐octadien‐1‐ol) as well as of nerol (( Z) ‐3,7‐dimethyl‐2,6‐octadien‐1‐ol). In the case of ( Z )‐2‐nonene‐1‐ol, the formation of ( E )‐2‐nonenal was detected as the only product. The isomerization of ( Z )‐2‐nonenal to the corresponding ( E )‐diastereomer with fungal lyophilisate under the applied reaction conditions has been shown in additional experiments. No products of further oxidation of the formed aldehydes or reduction of the activated CC‐double bond were detected in the reaction mixtures. A comparative analysis of the catalytic activity of lyophilisates obtained from Pleurotus sapidus and Pleurotus eryngii , as well‐known producers of oxidative enzymes, was performed in model experiments.

Whole‐cell cultures of the basidiomycetous white‐rot fungus Dichomitus albidofuscus exhibit varying catalytic activity towards aromatic compounds depending on the growth stage. This study reveals the catalytic behavior of mature whole‐cell cultures that effectively catalyze a C−C bond cleavage oxidizing toluene, benzaldehyde and acetophenone to phenol. The reaction products were analyzed by GC‐MS and NMR techniques. To exclude the de novo formation of phenol by the fungus, its origin has been proven by bioconversion of benzaldehyde‐d₅. The key step involves an aerobic Baeyer‐Villiger type rearrangement where the incorporation of oxygen into the product was confirmed based on isotope labelling experiments with ¹⁸O₂. Intermediate esters were not found in reaction mixture presumably due to the detected esterase activity in the mycelium as well as in supernatant of the whole‐cell cultures. As a result, the sequence of biocatalytic reactions catalyzed by D. albidofuscus for the degradation of toluene via C−C bond cleavage has been disclosed.

Aim. To perform a combined experimental and computational study on the luminescent properties of practically important class of organic dyes – 4-aminophthalimides. Results and discussion. The absorption and fluorescence spectra of 4-aminophthalimide derivatives in polar protic and aprotic solvents were computed and matched vs. the experimental data. The changes in emission spectra are mainly related to the NH₂-group derivatization. The methyl substitution of amide hydrogen causes a batochromic shift of about 7 nm in the absorption peak and a negligible hypsochromic shift in the fluorescence peak, while introducing alkyl substituents to the amine moiety causes bathochromic shifts in absorption and emission peaks of 30 – 40 nm and 10 – 60 nm, respectively. Experimental part. Absorption and emission wavelengths were computed by the standard algorithm based on the ground state geometry optimization (equilibrium solvation), vertical excitation with nonequilibrium solvation, and the TD-DFT geometry optimization of the excited state structures. A reliable hybrid B3LYP functional was used in combination with DZ and TZ-quality basis sets. Conclusions. The computed absorption wavelengths are in excellent agreement with the experimental data and are only slightly solvent-dependent. At the same time, the discrepancy with the experiment for Stokes shifts reaches about 20 % at IEF-PCM-TD-B3LYP/6-31G(d). However, the general tendency for both absorption and fluorescence wavelengths is identical for all solvents within one molecule. Received: 24.12.2019 Revised: 31.01.2020 Accepted: 27.02.2020