Browsing by Author "Dmytruk, Olena"

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    Engineering of Ogataea polymorpha strains with ability for high-temperature alcoholic fermentation of cellobiose
    (Oxford University Press, 2024-02-22) Vasylyshyn, Roksolana; Dmytruk, Olena; Sibirny, Andriy; Ruchała, Justyna
    Successful conversion of cellulosic biomass into biofuels requires organisms capable of efficiently utilizing xylose as well as cellodextrins and glucose. Ogataea (Hansenula) polymorpha is the natural xylose-metabolizing organism and is one of the most thermotolerant yeasts known, with a maximum growth temperature above 50°C. Cellobiose-fermenting strains, derivatives of an improved ethanol producer from xylose O. polymorpha BEP/cat8∆, were constructed in this work by the introduction of heterologous genes encoding cellodextrin transporters (CDTs) and intracellular enzymes (β-glucosidase or cellobiose phosphorylase) that hydrolyze cellobiose. For this purpose, the genes gh1-1 of β-glucosidase, CDT-1m and CDT-2m of cellodextrin transporters from Neurospora crassa and the CBP gene coding for cellobiose phosphorylase from Saccharophagus degradans, were successfully expressed in O. polymorpha. Through metabolic engineering and mutagenesis, strains BEP/cat8∆/gh1-1/CDT-1m and BEP/cat8∆/CBP-1/CDT-2mAM were developed, showing improved parameters for high-temperature alcoholic fermentation of cellobiose. The study highlights the need for further optimization to enhance ethanol yields and elucidate cellobiose metabolism intricacies in O. polymorpha yeast. This is the first report of the successful development of stable methylotrophic thermotolerant strains of O. polymorpha capable of coutilizing cellobiose, glucose, and xylose under high-temperature alcoholic fermentation conditions at 45°C.
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    Surowe dane badawcze do artykułu: Efficient production of bacterial antibiotics aminoriboflavin and roseoflavin in eukaryotic microorganisms, yeasts
    (BMC, Spinger Nature, 2023-07-20) Dmytruk, Kostyantyn; Ruchała, Justyna; Fayura, Liubov; Chrzanowski, Grzegorz; Dmytruk, Olena; Tsyrulnyk, Andriy; Andreieva, Yuliia; Fedorovych, Daria; Motyka, Olena; Mattanovich, Diethard; Marx, Hans; Sibirny, Andriy
    Background Actinomycetes Streptomyces davaonensis and Streptomyces cinnabarinus synthesize a promising broad-spectrum antibiotic roseoflavin, with its synthesis starting from flavin mononucleotide and proceeding through an immediate precursor, aminoriboflavin, that also has antibiotic properties. Roseoflavin accumulation by the natural producers is rather low, whereas aminoriboflavin accumulation is negligible. Yeasts have many advantages as biotechnological producers relative to bacteria, however, no recombinant producers of bacterial antibiotics in yeasts are known. Results Roseoflavin biosynthesis genes have been expressed in riboflavin- or FMN-overproducing yeast strains of Candida famata and Komagataella phaffii. Both these strains accumulated aminoriboflavin, whereas only the latter produced roseoflavin. Aminoriboflavin isolated from the culture liquid of C. famata strain inhibited the growth of Staphylococcus aureus (including MRSA) and Listeria monocytogenes. Maximal accumulation of aminoriboflavin in shake-flasks reached 1.5 mg L− 1 (C. famata), and that of roseoflavin was 5 mg L− 1 (K. phaffii). Accumulation of aminoriboflavin and roseoflavin by K. phaffii recombinant strain in a bioreactor reached 22 and 130 mg L− 1, respectively. For comparison, recombinant strains of the native bacterial producer S. davaonensis accumulated near one-order less of roseoflavin while no recombinant producers of aminoriboflavin was reported at all. Conclusions Yeast recombinant producers of bacterial antibiotics aminoriboflavin and roseoflavin were constructed and evaluated.