Ústav chemie potravin a biotechnologií

Browse

Now showing 1 - 5 of 91

Polyhydroxyalkanoate involvement in stress-survival of two psychrophilic bacterial strains from the High Arctic
(Springer, 2024-05-04) Grzesiak, Jakub; Rogala, Małgorzata Marta; Gawor, Jan; Kouřilová, Xenie; Obruča, Stanislav
An ever-growing body of literature evidences the protective role of polyhydroxyalkanoates (PHAs) against a plethora of mostly physical stressors in prokaryotic cells. To date, most of the research done involved bacterial strains isolated from habitats not considered to be life-challenging or extremely impacted by abiotic environmental factors. Polar region microorganisms experience a multitude of damaging factors in combinations rarely seen in other of Earth's environments. Therefore, the main objective of this investigation was to examine the role of PHAs in the adaptation of psychrophilic, Arctic-derived bacteria to stress conditions. Arctic PHA producers: Acidovorax sp. A1169 and Collimonas sp. A2191, were chosen and their genes involved in PHB metabolism were deactivated making them unable to accumulate PHAs (Delta phaC) or to utilize them (Delta i-phaZ) as a carbon source. Varying stressors were applied to the wild-type and the prepared mutant strains and their survival rates were assessed based on CFU count. Wild-type strains with a functional PHA metabolism were best suited to survive the freeze-thaw cycle - a common feature of polar region habitats. However, the majority of stresses were best survived by the Delta phaC mutants, suggesting that the biochemical imbalance caused by the lack of PHAs induced a permanent cell-wide stress response thus causing them to better withstand the stressor application. Delta i-phaZ mutants were superior in surviving UV irradiation, hinting that PHA granule presence in bacterial cells is beneficial despite it being biologically inaccessible. Obtained data suggests that the ability to metabolize PHA although important for survival, probably is not the most crucial mechanism in the stress-resistance strategies arsenal of cold-loving bacteria. Key points PHA metabolism helps psychrophiles survive freezing PHA-lacking psychrophile mutants cope better with oxidative and heat stresses PHA granule presence enhances the UV resistance of psychrophiles
AUTHENTICITY OF WINES PRODUCED FROM 'FRANKOVKA' GRAPE VARIETY ORIGINATING IN THE MODRÉ HORY REGION (CZECH REPUBLIC)
(POZNAN UNIV LIFE SCIENCES, 2024-11-29) Diviš, Pavel; Pořízka, Jaromír; Gross, Michal; Fojt, Lukáš; Vítová, Eva
Background. The geographical authenticity of wine, often referred to as terroir, is crucial in determining its unique characteristics and quality. Terroir encompasses the environmental factors where the grapes are grown, including soil composition, climate, and topography. These factors influence the flavor, aroma, and overall profile of the wine, giving it characteristics that are unique to its region of origin. Establishing geographical authenticity helps protect wine heritage, ensures quality control, and enhances market value. This study analyzed the phenolic, volatile, and elemental composition of wines with original certification (WOC) from the Modr & eacute; Hory region (MH) and compared them with wines from other Morava wine regions. Materials and methods. The study analyzed 24 wines of the 'Frankovka' variety from the Morava wine region, with 12 of these wines originating from the MH region with WOC certification. The researchers used Solid-Phase Microextraction coupled with Gas Chromatography-Mass Spectrometry, High-Performance Liquid Chromatography, Inductively Coupled Plasma Optical Emission Spectroscopy, and Inductively Coupled Plasma Mass Spectrometry techniques for the analysis. Results. Phenolic analysis revealed that MHWOC wines had significantly lower resveratrol levels, likely because of lower rainfall in the MH region. Volatile compound analysis reliably identified 38 substances, with MHWOC wines showing significant differences in the levels of ethyl octanoate, ethyl hexanoate, ethyl decanoate, and ethyl butyrate, attributed to unique production practices. Elemental analysis indicated higher Mg concentrations in MHWOC wines which were related to the region's clay and loess soils, whereas other wines from the Morava wine region exhibited higher levels of Sc, Ti, Fe, K, V, and Y due to different soil compositions. Conclusion. This study highlights the influence of regional soil and climate on wine composition and the potential of these parameters for the geographical authentication of wine. Based on the analysis, principal component analysis (PCA) reliably distinguished MHWOC wines from other wines originating from the
Comparative Study of Water and Milk Kefir Grains as Biopolymeric Adsorbents for Copper(II) and Arsenic(V) Removal from Aqueous Solutions
(MDPI, 2024-11-28) György, Balázs; Bujdoš, Marek; Vojtková, Hana; Diviš, Pavel; Slaný, Michal; Matúš, Peter; Urík, Martin
This study investigates the biosorption capabilities of kefir grains, a polysaccharide-based byproduct of the fermentation process, for removing copper(II) and arsenic(V) from contaminated water. Unlike traditional heavy-metal removal methods, which are typically expensive and involve environmentally harmful chemicals, biopolymeric materials such as kefir grains provide a sustainable and cost-effective alternative for adsorbing hazardous inorganic pollutants from aqueous solutions. Our experimental results revealed significant differences in the sorption capacities of two types of kefir grains. Grains of milk kefir outperformed water kefir, particularly in copper(II) removal, achieving up to 95% efficiency at low copper concentrations (0.16 mmolL-1) and demonstrating a maximum sorption capacity of 49 mu molg-1. In contrast, water kefir grains achieved only 35.5% maximum removal efficiency and exhibited lower sorption capacity. For arsenic(V) removal, milk kefir grains also showed superior performance, removing up to 56% of arsenic in diluted solution with experimental sorption capacities reaching up to 20 mu molg-1, whereas water kefir grains achieved a maximum removal efficiency of 34.5%. However, these findings also suggest that while kefir grains show potential as low-cost biosorbents, further modifications are needed to enhance their competitiveness for large-scale water treatment applications.
Iodine Accumulation and Distribution in Carrots (Daucus carota L.)
(MDPI, 2024-12-18) Duborská, Eva; Bujdoš, Marek; Matúš, Peter; Diviš, Pavel; Urík, Martin
Iodine is a critical trace element necessary for human and animal health owing to its role in thyroid hormone synthesis. Despite its importance, iodine deficiency remains a global health concern. Traditional methods to address this issue, such as salt iodization, face challenges like iodine loss during storage and cooking. The biofortification of plants, particularly carrots, offers a promising alternative. This study investigates iodine accumulation and distribution in carrots biofortified with potassium iodide (KI) and potassium iodate (KIO3) using single extraction at elevated temperatures with tetramethylammonium hydroxide followed by iodine determination by ICP-MS. Results show that iodine biofortification significantly increases the iodine content of various parts of the carrot, especially the leaves and the root peels. Carrots treated with iodate accumulate 2.7 times more iodine than those treated with iodide. The leaves exhibit the highest iodine content, particularly in iodate-treated plants, where levels can be over 24 times higher than those of control carrots. Root peel and roots also accumulate substantial amounts of iodine, with the iodate treatment resulting in 5.42 mgkg-1 and 3.75 mgkg-1 dry weight, respectively. The potential application of biofortified carrots can help meet human dietary iodine requirements; additionally, iodine-rich carrot leaves as livestock feed offer a sustainable approach to increasing the iodine intake in animals.
Evaluating stress resilience of cyanobacteria through flow cytometry and fluorescent viability assessment
(Sringer, 2024-11-06) Kroupová, Zuzana; Slaninová, Eva; Mrázová, Kateřina; Krzyžánek, Vladislav; Hrubanová, Kamila; Fritz, Ines; Obruča, Stanislav
Cyanobacteria are prokaryotic organisms characterised by their complex structures and a wide range of pigments. With their ability to fix CO2, cyanobacteria are interesting for white biotechnology as cell factories to produce various high-value metabolites such as polyhydroxyalkanoates, pigments, or proteins. White biotechnology is the industrial production and processing of chemicals, materials, and energy using microorganisms. It is known that exposing cyanobacteria to low levels of stressors can induce the production of secondary metabolites. Understanding of this phenomenon, known as hormesis, can involve the strategic application of controlled stressors to enhance the production of specific metabolites. Consequently, precise measurement of cyanobacterial viability becomes crucial for process control. However, there is no established reliable and quick viability assay protocol for cyanobacteria since the task is challenging due to strong interferences of autofluorescence signals of intercellular pigments and fluorescent viability probes when flow cytometry is used. We performed the screening of selected fluorescent viability probes used frequently in bacteria viability assays. The results of our investigation demonstrated the efficacy and reliability of three widely utilised types of viability probes for the assessment of the viability of Synechocystis strains. The developed technique can be possibly utilised for the evaluation of the importance of polyhydroxyalkanoates for cyanobacterial cultures with respect to selected stressor-repeated freezing and thawing. The results indicated that the presence of polyhydroxyalkanoate granules in cyanobacterial cells could hypothetically contribute to the survival of repeated freezing and thawing.

Browse

Recent Submissions