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

OBJECTIVE: The aim of the study was to find a possible association between the β- and κ-casein and β-lactoglobulin genotypes and important milk physiochemical and technological characteristics such as acidity, alcohol stability, the contents of some minerals and the parameters of acid fermentation ability (FEA) in Czech Fleckvieh Cattle. METHODS: Milk and blood samples were collected from 338 primiparous Czech Fleckvieh cows at the same stage of lactation. The genotypes of individual cows for κ-casein (alleles A, B, and E) and β-lactoglobulin (alleles A and B) were ascertained by polymerase chain reaction-restriction fragment length polymorphism, while their β-casein (alleles A1, A2, A3, and B) genotype was determined using melting curve genotyping analysis. The data collected were i) milk traits including active acidity (pH), titratable acidity (TA), alcohol stability (AS); calcium (Ca), phosphorus (P), sodium (Na), magnesium (Mg), and potassium (K) contents; and ii) yoghurt traits including active acidity (Y-pH), titratable acidity (Y-TA), and the counts of both Lactobacilli and Streptococci in 1 mL of yoghurt. A linear model was assumed with fixed effects of herd, year, and season of calving, an effect of the age of the cow at first calving and effects of the casein and lactoglobulin genotypes of β-CN (β-casein, CSN2), κ-CN (κ-casein, CSN3), and β-LG (β-lactoglobulin, LGB), or the three-way interaction between those genes. RESULTS: The genetic polymorphisms were related to the milk TA, AS, content of P and Ca, Y-pH and Lactobacilli number in the fresh yoghurt. The CSN3 genotype was significantly associated with milk AS (p<0.05). The effect of the composite CSN2-CSN3-LGB genotype on the investigated traits mostly reflected the effects of the individual genes. It significantly influenced TA (p<0.01), Y-pH (p<0.05) and the log of the Lactobacilli count (p<0.05). CONCLUSION: Our findings indicate that the yoghurt fermentation test together with milk proteins genotyping could contribute to milk quality control and highlight new perspectives in dairy cattle selection.

• Klíčová slova
• Acid Fermentation, Cattle, Genotype, Milk Acidity, Milk Protein,
• Publikační typ
• časopisecké články MeSH

The ciliate Diploplastron affine is known as a common species of the rumen fauna in cattle and sheep. This protozoon is able to digest cellulose, whereas its amylolytic activity is not well known. The objective of the reported studies was to examine the ability of D. affine to digest starch and to use this polysaccharide to cover the requirement for energy. The enzymatic studies showed that the protozoal cell extract degraded starch to reducing products with the rate being equivalent to 2.4 ± 0.47 μmol/L glucose per mg protein per min. Maltose, maltotriose and a small quantity of glucose were the end products of starch degradation. The degradation rate of maltose was only 0.05 μmol/L glucose per mg protein per min. Two peaks in α-amylase and a single peak in maltase activity were found following molecular filtration of ciliate cell extract, whereas three starch-degrading enzymes were identified by a zymographic technique. Incubation of the bacteria-free ciliates with starch in the presence of antibiotics resulted in a release of volatile fatty acids with the net rate of 25 pmol per protozoan per h. Acetic acid followed by butyric acid was the main product of starch fermentation. The results confirmed the ability of D. affine to utilize starch in energy-yielding processes.

• MeSH
• bachor parazitologie   MeSH
• Ciliophora enzymologie   metabolismus   MeSH
• fermentace MeSH
• ovce MeSH
• protozoální proteiny metabolismus   MeSH
• škrob metabolismus   MeSH
• trávení MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• protozoální proteiny MeSH
• škrob MeSH

In this study, the effects of seven pure plant secondary metabolites (PSMs) on rumen fermentation, methane (CH4 ) production and rumen bacterial community composition were determined. Two in vitro trials were conducted. In trial 1, nine concentrations of 8-hydroxyquinoline, α-terpineol, camphor, bornyl acetate, α-pinene, thymoquinone and thymol were incubated on separate days using in vitro 24-hr batch incubations. All compounds tested demonstrated the ability to alter rumen fermentation parameters and decrease CH4 production. However, effective concentrations differed among individual PSMs. The lowest concentrations that reduced (p < .05) CH4 production were as follows: 8 mg/L of 8-hydroxyquinoline, 120 mg/L of thymoquinone, 240 mg/L of thymol and 480 mg/L of α-terpineol, camphor, bornyl acetate and α-pinene. These concentrations were selected for use in trial 2. In trial 2, PSMs were incubated in one run. Methane was decreased (p < .05) by all PSMs at selected concentrations. However, only 8-hydroxyquinoline, bornyl acetate and thymoquinone decreased (p < .05) CH4 relative to volatile fatty acids (VFAs). Based on denaturing gradient gel electrophoresis analysis, different PSMs changed the composition of bacterial communities to different extents. As revealed by Ion Torrent sequencing, the effects of PSMs on relative abundance were most pronounced in the predominant families, especially in Lachnospiraceae, Succinivibrionaceae, Prevotellaceae, unclassified Clostridiales and Ruminococcaceae. The CH4 production was correlated negatively (-.72; p < .05) with relative abundance of Succinivibrionaceae and positively with relative abundance of Ruminococcaceae (.86; p < .05). In summary, this study identified three pure PSMs (8hydroxyquinoline, bornyl acetate and thymoquinone) with potentially promising effects on rumen CH4 production. The PSMs tested in this study demonstrated considerable impact on rumen bacterial communities even at the lowest concentrations that decreased CH4 production. The findings from this study may help to elucidate how PSMs affect rumen bacterial fermentation.

• Klíčová slova
• Ion Torrent, alkaloid, essential oil, methane, rumen bacteria, rumen fermentation,
• MeSH
• bachor metabolismus   mikrobiologie   MeSH
• dieta veterinární   MeSH
• dusík metabolismus   MeSH
• fermentace * MeSH
• fyziologie bakterií MeSH
• kyseliny mastné těkavé metabolismus   MeSH
• lipnicovité metabolismus   MeSH
• methan biosyntéza   MeSH
• skot MeSH
• zvířata MeSH
• Check Tag
• skot MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• dusík MeSH
• kyseliny mastné těkavé MeSH
• methan MeSH

S. kudriavzevii has potential for fermentations and other biotechnological applications, but is sensitive to many types of stress. We tried to increase its tolerance and performance via the expression of various transporters from different yeast species. Whereas the overexpression of Z. rouxii fructose uptake systems (ZrFfz1 and ZrFsy1) or a glycerol importer (ZrStl1) did not improve the ability of S. kudriavzevii to consume fructose and survive osmotic stress, the expression of alkali-metal-cation exporters (ScEna1, ScNha1, YlNha2) improved S. kudriavzevii salt tolerance, and that of ScNha1 also the fermentation performance. The level of improvement depended on the type and activity of the transporter suggesting that the natural sensitivity of S. kudriavzevii cells to salts is based on a non-optimal functioning of its own transporters.

• Klíčová slova
• Alkali-metal-cation exporter, Ena ATPase, Fermentation, Nha1 antiporter, Non-conventional yeasts, Salt tolerance,
• MeSH
• fermentace MeSH
• fruktosa metabolismus   MeSH
• glycerol metabolismus   MeSH
• iontový transport fyziologie   MeSH
• osmotický tlak fyziologie   MeSH
• proteiny přenášející kationty genetika   metabolismus   MeSH
• Saccharomyces metabolismus   MeSH
• sušené kvasnice MeSH
• tolerance k soli fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• fruktosa MeSH
• glycerol MeSH
• proteiny přenášející kationty MeSH

This review emphasises the fact that studies of acetone-butanol-ethanol (ABE) fermentation by solventogenic clostridia cannot be limited to research on the strain Clostridium acetobutylicum ATCC 824. Various 1-butanol producing species of the genus Clostridium, which differ in their patterns of product formation and abilities to ferment particular carbohydrates or glycerol, are described. Special attention is devoted to species and strains that do not produce acetone naturally and to the utilisation of lactose, inulin, glycerol and mixtures of pentose and hexose carbohydrates. Furthermore, process-mapping tools based on different principles, including flow cytometry, DNA microarray analysis, mass spectrometry, Raman microscopy, FT-IR spectroscopy and anisotropy of electrical polarisability, which might facilitate fermentation control and a deeper understanding of ABE fermentation, are introduced. At present, the methods with the greatest potential are flow cytometry and transcriptome analysis. Flow cytometry can be used to visualise and capture cells within clostridial populations as they progress through the normal cell cycle, in which symmetric and asymmetric cell division phases alternate. Cell viability of a population of Clostridium pasteurianum NRRL B-598 was determined by flow cytometry. Transcriptome analysis has been used in various studies including the detection of genes expressed in solventogenic phase, at sporulation, in the stress response, to compare expression patterns of different strains or parent and mutant strains, for studies of catabolite repression, and for the detection of genes involved in the transport and metabolism of 11 different carbohydrates. Interestingly, the results of transcriptome analysis also challenge our earlier understanding of the role of the Spo0A regulator in initiation of solventogenesis in C. acetobutylicum ATCC 824. Lastly, the review describes other significant recent discoveries, including the deleterious effects of intracellular formic acid accumulation in C. acetobutylicum DSM 1731 cells on the metabolic switch from acidogenesis to solventogenesis and the development of a high-cell density continuous system using Clostridium saccharoperbutylacetonicum N1-4, in which 1-butanol productivity of 7.99 g/L/h was reached.

• MeSH
• aceton metabolismus   MeSH
• butanoly metabolismus   MeSH
• Clostridium cytologie   genetika   metabolismus   MeSH
• ethanol metabolismus   MeSH
• fermentace * MeSH
• glycerol metabolismus   MeSH
• hexosy metabolismus   MeSH
• inulin metabolismus   MeSH
• laktosa metabolismus   MeSH
• pentosy metabolismus   MeSH
• průtoková cytometrie MeSH
• Ramanova spektroskopie MeSH
• sekvenční analýza hybridizací s uspořádaným souborem oligonukleotidů MeSH
• spektroskopie infračervená s Fourierovou transformací MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• aceton MeSH
• butanoly MeSH
• ethanol MeSH
• glycerol MeSH
• hexosy MeSH
• inulin MeSH
• laktosa MeSH
• pentosy MeSH

Biotechnological conversion of low-cost agro-industrial by-products, such as industrial waste or terpenes from the distillation of essential oils from plants into more valuable oxygenated derivatives, can be achieved by using microbial cells or enzymes. In Argentina, the essential oil industry produces several tons of waste each year that could be used as raw materials in the production of industrially relevant and value-added compounds. In this study, 1,8-cineole, one of the components remaining in the spent leaves of the Eucalyptus cinerea waste, was transformed by solid-state fermentation (SSF) using the two edible mushrooms Pleurotus ostreatus and Favolus tenuiculus. As a result, two new oxygenated derivatives of 1,8-cineole were identified: 1,3,3-trimethyl-2-oxabicyclo [2.2.2]octan-6-ol and 1,3,3-trimethyl-2-oxabicyclo [2.2.2]octan-6-one. Additionally, changes in the relative percentages of other aroma compounds present in the substrate were observed during SSF. Both fungal strains have the ability to produce aroma compounds with potential applications in the food and pharmaceutical industries.

• Klíčová slova
• 1,8-cineole, Biotransformation, Favolus tenuiculus, Industrial waste, Pleurotus ostreatus, Solid state fermentation,
• MeSH
• biotransformace MeSH
• cyklohexanoly chemie   metabolismus   MeSH
• Eucalyptus metabolismus   mikrobiologie   MeSH
• eukalyptol MeSH
• fermentace MeSH
• monoterpeny chemie   metabolismus   MeSH
• oleje prchavé analýza   MeSH
• Pleurotus metabolismus   MeSH
• Polyporaceae metabolismus   MeSH
• průmyslový odpad analýza   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• cyklohexanoly MeSH
• eukalyptol MeSH
• monoterpeny MeSH
• oleje prchavé MeSH
• průmyslový odpad MeSH

The objective of this study was to investigate the effects of 11 active compounds of essential oils (ACEO) on rumen fermentation characteristics and methane production. Two trials were conducted. In trial 1, ACEO (eugenol, carvacrol, citral, limonene, 1,4-cineole, p-cymene, linalool, bornyl acetate, α-pinene, and β-pinene) at a dose of 1,000 μL/L were incubated for 24 h in diluted rumen fluid with a 70:30 forage:concentrate substrate (16.2% crude protein; 36.6% neutral detergent fiber). Three fistulated Holstein cows were used as donors of rumen fluid. The reduction in methane production was observed with nine ACEO (up to 86% reduction) compared with the control (p<0.05). Among these, only limonene, 1,4-cineole, bornyl acetate, and α-pinene did not inhibit volatile fatty acid (VFA) production, and only bornyl acetate produced less methane per mol of VFA compared with the control (p<0.05). In a subsequent trial, the effects on rumen fermentation and methane production of two concentrations (500 and 2,000 μL/L) of bornyl acetate, the most promising ACEO from the first trial, were evaluated using the same in vitro incubation method that was used in the first trial. In trial 2, monensin was used as a positive control. Both doses of bornyl acetate decreased (p<0.05) methane production and did not inhibit VFA production. Positive effects of bornyl acetate on methane and VFA production were more pronounced than the effects of monensin. These results confirm the ability of bornyl acetate to decrease methane production, which may help to improve the efficiency of energy use in the rumen.

• Klíčová slova
• Bornyl Acetate, Essential Oil Active Compounds, Methane Production, Rumen Fermentation, Volatile Fatty Acid Production,
• Publikační typ
• časopisecké články MeSH

The net effect of increased wort osmolarity on fermentation time, bottom yeast vitality and sedimentation, beer flavor compounds, and haze was determined in fermentations with 12 degrees all-malt wort supplemented with sorbitol to reach osmolarity equal to 16 degrees and 20 degrees. Three pitchings were performed in 12 degrees/12 degrees/12 degrees, 16 degrees/16 degrees/12 degrees, and 20 degrees/20 degrees/12 degrees worts. Fermentations in 16 degrees and 20 degrees worts decreased yeast vitality measured as acidification power (AP) by a maximum of 10%, lowered yeast proliferation, and increased fermentation time. Repitching aggravated these effects. The 3rd "back to normal" pitching into 12 degrees wort restored the yeast AP and reproductive abilities while the extended fermentation time remained. Yeast sedimentation in 16 degrees and 20 degrees worts was delayed but increased about two times at fermentation end relative to that in 12 degrees wort. Third "back-to-normal" pitching abolished the delay in sedimentation and reduced its extent, which became nearly equal in all variants. Beer brewed at increased osmolarity was characterized by increased levels of diacetyl and pentanedione and lower levels of dimethylsulfide and acetaldehyde. Esters and higher alcohols displayed small variations irrespective of wort osmolarity or repitching. Increased wort osmolarity had no appreciable effect on the haze of green beer and accelerated beer clarification during maturation. In all variants, chill haze increased with repitching.

• MeSH
• acetaldehyd analýza   MeSH
• alkoholy analýza   MeSH
• časové faktory MeSH
• chuť MeSH
• diacetyl analýza   MeSH
• estery analýza   MeSH
• fermentace MeSH
• mikrobiální viabilita MeSH
• osmotický tlak * MeSH
• pentany analýza   MeSH
• pivo analýza   mikrobiologie   MeSH
• Saccharomyces fyziologie   MeSH
• sulfidy analýza   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• acetaldehyd MeSH
• alkoholy MeSH
• diacetyl MeSH
• dimethyl sulfide MeSH Prohlížeč
• estery MeSH
• pentany MeSH
• sulfidy MeSH

Bifidobacteria (246 strains in total) were isolated from rectal samples of infants and adult humans and animals, and from intestinal samples of calves. Twenty-five strains grew well on mucin: 20 from infants, two from adults, and three from goatlings. Poor or no growth on mucin was observed in 156 bifidobacterial strains of animal origin. The difference between human and animal isolates in ability to grow on mucin was significant at p < 0.001. Nine human strains with the best growth on mucin were identified as Bifidobacterium bifidum. These strains produced extracellular, membrane-bound, and intracellular mucinases with activities of 0.11, 0.53, and 0.09 μmol/min of reducing sugars per milligram of protein, respectively. Membrane-bound mucinases were active between pH 5 and 10. The optimum pH of extracellular mucinases was 6-7. Fermentation patterns in cultures grown on mucin and glucose differed. On mucin, the acetate-to-lactate ratio was higher than in cultures grown on glucose (p = 0.012). We showed that the bifidobacteria belong to the mucin-fermenting bacteria in humans, but their significance in mucin degradation in animals seems to be limited.

• MeSH
• Bifidobacterium enzymologie   genetika   izolace a purifikace   metabolismus   MeSH
• dospělí MeSH
• fermentace MeSH
• glukosa metabolismus   MeSH
• kojenec MeSH
• koncentrace vodíkových iontů MeSH
• kozy MeSH
• lidé MeSH
• muciny metabolismus   MeSH
• polysacharid-lyasy chemie   metabolismus   MeSH
• skot MeSH
• stabilita enzymů MeSH
• teplota MeSH
• tlusté střevo mikrobiologie   MeSH
• zvířata MeSH
• Check Tag
• dospělí MeSH
• kojenec MeSH
• lidé MeSH
• skot MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• glukosa MeSH
• hyaluronate lyase MeSH Prohlížeč
• muciny MeSH
• polysacharid-lyasy MeSH