How microorganisms use hydrophobicity and what does this mean for human needs?

Cell surface hydrophobicity (CSH) plays a crucial role in the attachment to, or detachment from the surfaces. The influence of CSH on adhesion of microorganisms to biotic and abiotic surfaces in medicine as well as in bioremediation and fermentation industry has both negative and positive aspects. Hydrophobic microorganisms cause the damage of surfaces by biofilm formation; on the other hand, they can readily accumulate on organic pollutants and decompose them. Hydrophilic microorganisms also play a considerable role in removing organic wastes from the environment because of their high resistance to hydrophobic chemicals. Despite the many studies on the environmental and metabolic factors affecting cell surface hydrophobicity (CSH), the knowledge of this subject is still scanty and is in most cases limited to observing the impact of hydrophobicity on adhesion, aggregation or flocculation. The future of research seems to lie in finding a way to managing the microbial adhesion process, perhaps by steering cell hydrophobicity

Waste Brewery and Winery Yeast as a Raw Material for Biotechnological Productions

Yeast of the genus Saccharomyces is the most commonly used organism in the production of biotechnological products, and its amount produced in the production of beer and wine is enormous. It is reported that the worldwide annual production of both beverages entails the production of more than half a million tons of yeast, calculated on dry matter, the largest production of any microorganism worldwide. For this reason, it could be used as a potential secondary raw material. In the following review, we focus on the use of waste yeast biomass, particularly in terms of its processing into biofuels, especially biodiesel. Particular attention is also paid to the use of yeast as a source of sophisticated products, especially squalene and palmitoleic acid, an important raw material that can be used as a biodiesel additive, but also in cosmetic and dietetic products

A method for determining the effect of osmotic stress on the physiological state of brewer´s yeast and the course of main fermentation

The methodology concerns a laboratory assay of the response of production strains of brewer´s yeast to high osmotic pressure common for the HGB (high gravity brewing) process. It is intended for brewery laboratories with good instrumental background, which are engaged in characterizing producrion strains and evaluating their suitability for use in new technologies. Application of the methodology extends the spectrum of methods used for the description of production yeast strain

Virtual Interactomics of Proteins from Biochemical Standpoint

Virtual interactomics represents a rapidly developing scientific area on the boundary line of bioinformatics and interactomics. Protein-related virtual interactomics then comprises instrumental tools for prediction, simulation, and networking of the majority of interactions important for structural and individual reproduction, differentiation, recognition, signaling, regulation, and metabolic pathways of cells and organisms. Here, we describe the main areas of virtual protein interactomics, that is, structurally based comparative analysis and prediction of functionally important interacting sites, mimotope-assisted and combined epitope prediction, molecular (protein) docking studies, and investigation of protein interaction networks. Detailed information about some interesting methodological approaches and online accessible programs or databases is displayed in our tables. Considerable part of the text deals with the searches for common conserved or functionally convergent protein regions and subgraphs of conserved interaction networks, new outstanding trends and clinically interesting results. In agreement with the presented data and relationships, virtual interactomic tools improve our scientific knowledge, help us to formulate working hypotheses, and they frequently also mediate variously important in silico simulations

Beer-spoiling ability of lactic acid bacteria and its relation with genes horA, horC and hitA.

Beer-spoiling ability, survival after 14 weeks of incubation in 2 beer types under 2 temperature regimes and the presence of spoilageassociated horA, horC and hitA genes in the genome were studied in 69 strains of lactic acid bacteria. Beer spoilage was determined in 12 (48 %) of 25 strains of Lactobacillus brevis, 2 (25 %) of 8 strains of L. plantarum, 7 (26 %) of 27 strains of L. paracasei subsp. paracasei, and in 1 (33 %) of 3 strains of Leuconostoc spp. Survival in beer without adverse effects on its quality was more widely spread among the strains (L. brevis 89 %, L. plantarum 75 %, L. buchneri 100 %, L. paracasei subsp. paracasei 82 %, L. lactis 66 %, Leuconostoc spp. 33 %). In the strongest beer spoiler L. brevis, beer spoilage was observed only in 2 strains containing horC and in 6 strains containing the combinations horA/hitA and horA/horC/hitA; 4 strains spoiled beer without having any of these genes. Beer spoilage, detected in a total of 10 strains of all other species, was not associated with the presence of these genes.Beer-spoiling ability, survival after 14 weeks of incubation in 2 beer types under 2 temperature regimes and the presence of spoilageassociated horA, horC and hitA genes in the genome were studied in 69 strains of lactic acid bacteria. Beer spoilage was determined in 12 (48 %) of 25 strains of Lactobacillus brevis, 2 (25 %) of 8 strains of L. plantarum, 7 (26 %) of 27 strains of L. paracasei subsp. paracasei, and in 1 (33 %) of 3 strains of Leuconostoc spp. Survival in beer without adverse effects on its quality was more widely spread among the strains (L. brevis 89 %, L. plantarum 75 %, L. buchneri 100 %, L. paracasei subsp. paracasei 82 %, L. lactis 66 %, Leuconostoc spp. 33 %). In the strongest beer spoiler L. brevis, beer spoilage was observed only in 2 strains containing horC and in 6 strains containing the combinations horA/hitA and horA/horC/hitA; 4 strains spoiled beer without having any of these genes. Beer spoilage, detected in a total of 10 strains of all other species, was not associated with the presence of these genes

Vitality and viability of pitching yeast: methods of assessment and the effect of cellular stress resistance systems.

The article concerns two main topics: 1. Assessment of viability and metabolic competence of yeast by the acidification power test (AP test), its biochemical background, conditions of its use and its development since its introduction, and 2. The way in which the metabolic competence of pitching yeast, and hence the results of the AP test, can be affected by, e.g., the yeast growth phase and the status of the multidrug resistance system (MDR) which underlies the ability of cells to cope with chemical stress caused by xenobiotics. The AP test developed and patented by Opekarová and Sigler, and used by them for the first time to assess the metabolic competence repeatedly pitched in the brewing process, is based on the knowledge of membrane processes taking place in yeast cells metabolizing endogenous and exogenous substrates. The main process contributing to the acidification power of yeast, i.e. the activity of the H+-ATPase, depends not only on cell condition (fresh cells, cells after storage, washing, etc.) but very strongly also on the growth phase. During and closely after the diauxic shift the activity of H+-ATPase in S. cerevisiae sharply drops and remains low during the post-diauxic and stationary phases. This is due to the transition of the cells to an energy saving regime in which energetically demanding processes involving high ATP consumption are downregulated. The MDR transporters exhibit a similar activity pattern.The article concerns two main topics: 1. Assessment of viability and metabolic competence of yeast by the acidification power test (AP test), its biochemical background, conditions of its use and its development since its introduction, and 2. The way in which the metabolic competence of pitching yeast, and hence the results of the AP test, can be affected by, e.g., the yeast growth phase and the status of the multidrug resistance system (MDR) which underlies the ability of cells to cope with chemical stress caused by xenobiotics. The AP test developed and patented by Opekarová and Sigler, and used by them for the first time to assess the metabolic competence repeatedly pitched in the brewing process, is based on the knowledge of membrane processes taking place in yeast cells metabolizing endogenous and exogenous substrates. The main process contributing to the acidification power of yeast, i.e. the activity of the H+-ATPase, depends not only on cell condition (fresh cells, cells after storage, washing, etc.) but very strongly also on the growth phase. During and closely after the diauxic shift the activity of H+-ATPase in S. cerevisiae sharply drops and remains low during the post-diauxic and stationary phases. This is due to the transition of the cells to an energy saving regime in which energetically demanding processes involving high ATP consumption are downregulated. The MDR transporters exhibit a similar activity pattern

Convenient Monitoring Of Brewery Fermentation Course By Refractometry.

The course of wort fermentation is most often monitored by measuring density by immersion saccharometer or digital densitometer; other methods include classical analysis or automatic analyzers. Another possibility is the measurement of refraction in the course of fermentation. When the original refraction or wort extract is known, refraction unambiguously determines the apparent extract or degree of attenuation. A refractometer with a scale in Brix degrees can be used similarly as a saccharometer having a scale in mass percent of sucrose. In the range of 0-16 mass % sucrose and 0-8% ethanol refraction is a linear function of concentration; this allows us to calculate concentration of ethanol, real extract and also an apparent extract in the course of fermentation from the values of actual and original refraction. Examples are given of measurement and instrument calibration. The measurements can be done with simple and inexpensive refractometers with computing compensation of the effect of temperature.The course of wort fermentation is most often monitored by measuring density by immersion saccharometer or digital densitometer; other methods include classical analysis or automatic analyzers. Another possibility is the measurement of refraction in the course of fermentation. When the original refraction or wort extract is known, refraction unambiguously determines the apparent extract or degree of attenuation. A refractometer with a scale in Brix degrees can be used similarly as a saccharometer having a scale in mass percent of sucrose. In the range of 0-16 mass % sucrose and 0-8% ethanol refraction is a linear function of concentration; this allows us to calculate concentration of ethanol, real extract and also an apparent extract in the course of fermentation from the values of actual and original refraction. Examples are given of measurement and instrument calibration. The measurements can be done with simple and inexpensive refractometers with computing compensation of the effect of temperature

Production of Palmitoleic and Linoleic Acid in Oleaginous and Nonoleaginous Yeast Biomass

We investigated the possibility of utilizing both oleaginous yeast species accumulating large amounts of lipids (Yarrowia lipolytica, Rhodotorula glutinis, Trichosporon cutaneum, and Candida sp.) and traditional biotechnological nonoleaginous ones (Kluyveromyces polysporus, Torulaspora delbrueckii, and Saccharomyces cerevisiae) as potential producers of dietetically important major fatty acids. The main objective was to examine the cultivation conditions that would induce a high ratio of dietary fatty acids and biomass. Though genus-dependent, the type of nitrogen source had a higher influence on biomass yield than the C/N ratio. The nitrogen source leading to the highest lipid accumulation was potassium nitrate, followed by ammonium sulfate, which is an ideal nitrogen source supporting, in both oleaginous and nonoleaginous species, sufficient biomass growth with concomitantly increased lipid accumulation. All yeast strains displayed high (70–90%) content of unsaturated fatty acids in total cell lipids. The content of dietary fatty acids of interest, namely, palmitoleic acid and linoleic acid, reached in Kluyveromyces and Trichosporon strains over 50% of total fatty acids and the highest yield, over 280 mg per g of dry cell weight of these fatty acids, was observed in Trichosporon with ammonium sulfate as nitrogen source at C/N ratio 70