During alcoholic fermentation, a considerable amount of carbon dioxide (CO2) is produced, and the stream of CO2 can strip aromatic substances from the fermenting must. Aroma losses during fermentation can be significant and may lead to a reduction in wine quality. This study is focused on new fermentation gas capture technology. In the experiment, gas was captured during the fermentation of sauvignon blanc must. The concentration of individual volatile compounds in the fermentation gas was determined using gas chromatography, and the highest values were achieved by isoamyl acetate, isoamyl alcohol and ethyl decanoate. Ethyl dodecanoate achieved the lowest values of the investigated volatile substances. For sensory assessment, quantitative descriptive analysis (QDA) compared water carbonated with fermentation gas and water carbonated with commercial carbon dioxide for food purposes. Based on the results of this study, it can be concluded that the captured gas containing positive aromatic substances is suitable for the production of carbonated drinks in the food industry.

• Klíčová slova
• carbon dioxide, fermentation gas, must, volatile aroma compounds,
• Publikační typ
• časopisecké články MeSH

• Klíčová slova
• AMINO ACIDS *, CHEMISTRY, PHARMACEUTICAL *, CHROMATOGRAPHY *, ELECTROPHORESIS *, FERMENTATION *,
• MeSH
• aminokyseliny * MeSH
• chromatografie * MeSH
• elektroforéza * MeSH
• farmaceutická chemie * MeSH
• fermentace * MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• aminokyseliny * MeSH

This study focuses on the use of thermodynamic sensors (TDS) in baking, brewing, and yogurt production at home. Using thermodynamic sensors, a change in the temperature flow between the two sensor elements during fermentation was observed for the final mixture (complete recipe for pizza dough production), showing the possibility of distinguishing some phases of the fermentation process. Even during the fermentation process in the preparation of wort and yogurt with non-traditional additives, the sensors were able to indicate significant parts of the process, including the end of the process. The research article also mentions as a new idea the use of trivial regulation at home in food production to determine the course of the fermentation process. The results presented in this article show the possibility of using TDS for more accurate characterization and adjustment of the production process of selected foods in the basic phase, which will be further applicable in the food industry, with the potential to reduce the cost of food production processes that involve a fermentation process.

• Klíčová slova
• fermentation, thermodynamic sensors, yeast,
• MeSH
• fermentace MeSH
• jogurt * MeSH
• manipulace s potravinami * MeSH
• teplota MeSH
• termodynamika MeSH
• Publikační typ
• časopisecké články MeSH

• Klíčová slova
• FERMENTATION *,
• MeSH
• Candida * MeSH
• fermentace * MeSH
• Publikační typ
• časopisecké články MeSH

Pumping toxic substances through a cytoplasmic membrane by protein transporters known as efflux pumps represents one bacterial mechanism involved in the stress response to the presence of toxic compounds. The active efflux might also take part in exporting low-molecular-weight alcohols produced by intrinsic cell metabolism; in the case of solventogenic clostridia, predominantly acetone, butanol and ethanol (ABE). However, little is known about this active efflux, even though some evidence exists that membrane pumps might be involved in solvent tolerance. In this study, we investigated changes in overall active efflux during ABE fermentation, employing a flow cytometric protocol adjusted for Clostridia and using ethidium bromide (EB) as a fluorescence marker for quantification of direct efflux. A fluctuation in efflux during the course of standard ABE fermentation was observed, with a maximum reached during late acidogenesis, a high efflux rate during early and mid-solventogenesis and an apparent decrease in EB efflux rate in late solventogenesis. The fluctuation in efflux activity was in accordance with transcriptomic data obtained for various membrane exporters in a former study. Surprisingly, under altered cultivation conditions, when solvent production was attenuated, and extended acidogenesis was promoted, stable low efflux activity was reached after an initial peak that appeared in the stage comparable to standard ABE fermentation. This study confirmed that efflux pump activity is not constant during ABE fermentation and suggests that undisturbed solvent production might be a trigger for activation of pumps involved in solvent efflux. KEY POINTS: • Flow cytometric assay for efflux quantification in Clostridia was established. • Efflux rate peaked in late acidogenesis and in early solventogenesis. • Impaired solventogenesis led to an overall decrease in efflux.

• Klíčová slova
• ABE fermentation, Clostridium, Efflux pump, Ethidium bromide, Flow cytometry,
• MeSH
• aceton MeSH
• butanoly MeSH
• Clostridium beijerinckii * MeSH
• Clostridium MeSH
• ethanol MeSH
• fermentace MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• aceton MeSH
• butanoly MeSH
• ethanol MeSH

Methods for the design of tubular fermentation systems are summarized. The first part, on tubular system hydrodynamics, is concerned with the design methods for gas hold-up, pressure drop, drop-size distribution and actual interfacial area, and with non-ideal flow conditions. This being a critical review, only the more important methods have been selected. More recent design methods for the prediction of oxygen transfer coefficients in fermentation systems and methods of determining of true kinetic relations are also reviewed, accounting for the inevitable non-ideality of flow. General rules for system optimization are presented.

• MeSH
• Bacteria metabolismus   MeSH
• biologické modely * MeSH
• chemické inženýrství * MeSH
• fermentace * MeSH
• houby metabolismus   MeSH
• kinetika MeSH
• plyny MeSH
• tlak MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• plyny MeSH

Syngas fermentation to acetate offers a promising solution for its valorisation, particularly when syngas contains a high N2 concentration, which otherwise impedes the utilisation of syngas biomethanation gaseous product in cogeneration or upgrading units. In this study, continuous lab-scale syngas fermentation assessing the effects of acidic pH and psychrophilic conditions (28 °C and 20 °C) on bioconversion efficiency and anaerobic consortium diversity was studied. The results showed that as temperature and pH decrease, acetate yield increases. The highest H2 and CO consumption rates were observed at 20 °C and pH 4.5, reaching 48.4 mmol/(L·d) and 31.5 mmol/(L·d), respectively, and methanogenic activity was not completely suppressed. The microbial community composition indicated an enhanced abundance of acetate-producing bacteria and hydrogenotrophic methanogens at 28 °C. The PICRUSt2 prediction of metabolic potential indicated that temperature and pH changes appear to have a more pronounced impact on acetotrophic methanogenesis genes than carbon dioxide-based methanogenesis genes.

• Klíčová slova
• Acetate, Acidic, Anaerobic culture, Psychrophilic, Syngas fermentation,
• MeSH
• acetáty MeSH
• anaerobióza MeSH
• bioreaktory * mikrobiologie   MeSH
• fermentace MeSH
• methan metabolismus   MeSH
• plyny * MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• acetáty MeSH
• methan MeSH
• plyny * MeSH

The economics of producing energy-valuable gases by fermenting phytomass is deteriorated by the costs associated with waste management of highly diluted (typically 95% water) fermentation residues (FR). Previously, no better solution was known than to plough FR into the arable land and claim that it is an irrigation with soil improving and fertilizing effect. However, farmers soon realized that FR organic matter is of little agronomic value and nutrients are at agronomically insignificant levels. As FR watering has proved economically irrational in many countries the practice of separating water from the FR and using the solid fraction for energy purposes (such as charcoal) has dominated. However, most nutrients are lost in this way. For the first time it is proposed to activate the charred FR via calcium chloride (whose price is insignificant as it would be used for fertilization purposes anyway) and using the resulting sorbent to capture phosphorus (P) out of the FR's liquid fraction. It is reported for the first time that the activated char is capable of capturing 37.5 ± 4.7 kg P t-1 whereas the P availability for plant nutrition outperforms FR as well as struvite. In addition, the char demonstrates the potential to improve soil characteristics and the metabolism of soil biota. The cost breakdown and subsequent market analysis indicates that the novel fertilizer shows signs of competitiveness.

• Klíčová slova
• Circular economy, Competitiveness, Fermentation residues, Nutrient recovery, Tree fertilizer,
• MeSH
• biopaliva * MeSH
• fermentace MeSH
• fosfor * MeSH
• průmyslová hnojiva MeSH
• struvit MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• biopaliva * MeSH
• fosfor * MeSH
• průmyslová hnojiva MeSH
• struvit MeSH

• Klíčová slova
• FERMENTATION *, GLUCOSE *, MALTOSE *, SACCHAROMYCES *,
• MeSH
• fermentace * MeSH
• glukosa * MeSH
• maltosa * MeSH
• Saccharomyces cerevisiae * MeSH
• Saccharomyces * MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• glukosa * MeSH
• maltosa * MeSH

During yeast dough fermentation, such as the high-sucrose bread-making process, the yeast cells are subjected to considerable osmotic stress, resulting in poor outcomes. Invertase is important for catalyzing the irreversible hydrolysis of sucrose to free glucose and fructose, and decreasing the catalytic activity of the invertase may reduce the glucose osmotic stress on the yeast. In this study, we performed structural design and site-directed mutagenesis (SDM) on the Saccharomyces cerevisiae invertase (ScInV) in an Escherichia coli expression system to study the catalytic activity of ScInV mutants in vitro. In addition, we generated the same mutation sites in the yeast endogenous genome and tested their invertase activity in yeast and dough fermentation ability. Our results indicated that appropriately reduced invertase activity of yeast ScInV can enhance dough fermentation activity under high-sucrose conditions by 52%. Our systems have greatly accelerated the engineering of yeast endogenous enzymes both in vitro and in yeast, and shed light on future metabolic engineering of yeast.

• Klíčová slova
• Fermentation ability, Invertase activity, Protein engineering, Site-directed mutagenesis,
• MeSH
• fermentace MeSH
• glukosa metabolismus   MeSH
• invertasa * genetika   metabolismus   MeSH
• proteinové inženýrství MeSH
• Saccharomyces cerevisiae * metabolismus   MeSH
• sacharosa metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• glukosa MeSH
• invertasa * MeSH
• sacharosa MeSH