Physiological State Of Microorganisms Research Articles

RESEARCH OF TO ULTRATHIN STRUCTURE OF CAGES OF DIFFERENT RACES OF SPIRIT YEASTS IN DEPENDENCE ON CONCENTRATION OF DRY SUBSTANCES OF WAS

One of the directions of introduction of resource- and energy-saving technology of alcohol brews into alcohol production is the use of highly concentrated wort from grain raw materials. The use of highly productive strains of alcoholic yeast is the basis of resource- and energy-saving technologies, a way to reduce the cost of ethyl alcohol and increase the profitability of its production. To develop the technology of highly concentrated mash from grain raw materials, it is necessary to select and select the appropriate breeds of yeast and study their morphological and physiological properties. Diagnosis of the physiological state of microorganisms. The influence of wort dry matter concentration on morphological and cytological features of the structure of yeast cells of alcoholic breeds of yeast S. cerevisiae DO–16, DO–11, K–81, XII in the conditions of cultivation on media from starch-containing raw materials was studied. The concentration of dry matter of the wort is 20 and 28%. It was found that the selected race of yeast S. cerevisiae DO–16 synthesizes the largest number of yeast cells at a concentration of 28%. Osmophilic races of S. cerevisiae DO–16 and DO–11 had smaller cell sizes and areas in comparison with thermotolerant and mesophilic races of S. cerevisiae K–81 and XII at a wort concentration of 28.0%. During fermentation, these indicators characterize the increase in the working surface of the yeast in the fermented medium, it allows to accelerate the fermentation process and ensure microbiological purity of the environment, which is especially important for highly concentrated wort. On the basis of morphological and cytological studies of the yeast race S. cerevisiae DO–16, its advantages over the races DO –11, K–81, XII for fermentation of high-concentration wort have been proved. Based on studies of the intracellular structure of the yeast S. cerevisiae DO–16, DO–11, K–81, XII, the relationship between the formation of glycogen in yeast cells and the concentration of DM wort was established. When culturing industrial yeast at a DM concentration of 28%, the glycogen content in the cells of S. cerevisiae DO–16 was significantly higher compared to the studied races, which indicates favorable conditions of the culture medium for this race.

Simple Control Systems for Set-point Control of Dissolved Oxygen Concentration in Batch Fermentation Processes

Dissolved oxygen concentration (DOC) is one of the most important technological parameters of fermentation processes influencing the physiological state of microorganisms’ cultures, production of desired products and reproducibility of desired processes. However, automatic set-point control of DOC in batch and fed-batch fermentation processes is not a trivial control task, as the resulting dynamic parameters (gain coefficient, time constant and time delay) of the control channel “agitation speed – DOC” vary over a wide range, and the ordinary PI or PID controllers with fixed tuning parameters are insufficient for accurate control of DOC during the entire control course. In this text, two control approaches have been proposed for coping with the problems of nonlinear and non-stationary dynamics of the DOC control process.

Keys to Cultivating Uncultured Microbes: Elaborate Enrichment Strategies and Resuscitation of Dormant Cells

Keys to Cultivating Uncultured Microbes: Elaborate Enrichment Strategies and Resuscitation of Dormant Cells

Dead or alive: molecular assessment of microbial viability.

Nucleic acid-based analytical methods, ranging from species-targeted PCRs to metagenomics, have greatly expanded our understanding of microbiological diversity in natural samples. However, these methods provide only limited information on the activities and physiological states of microorganisms in samples. Even the most fundamental physiological state, viability, cannot be assessed cross-sectionally by standard DNA-targeted methods such as PCR. New PCR-based strategies, collectively called molecular viability analyses, have been developed that differentiate nucleic acids associated with viable cells from those associated with inactivated cells. In order to maximize the utility of these methods and to correctly interpret results, it is necessary to consider the physiological diversity of life and death in the microbial world. This article reviews molecular viability analysis in that context and discusses future opportunities for these strategies in genetic, metagenomic, and single-cell microbiology.

Distribution and Physiological State of Microorganisms in Petrochemical Oily Sludge

The occurrence, vertical distribution, and physiological state of microorganisms in a petrochemical oily sludge deposit were studied. The total number and the number of viable microbial cells at depths of 0.2 and 3 m were about 1010 and 108 cells/g dry wt sludge. Most microbial cells taken from the middle (1 m deep) and the bottom (3 m deep) sludge horizons showed a delayed colony-forming ability, which suggested that the cells occurred in a hypometabolic state. The relative number of microaerobic denitrifying microorganisms steeply increased with depth. The amount of microorganisms tolerant to 3, 5, and 10% NaCl and capable of growing at 7 and 40°C varied from 102 to 108 CFU/g dry wt sludge. Petrochemical oily sludge was found to maintain the growth of heterotrophs, among which the degraders of oily sludge and ten different individual polycyclic aromatic hydrocarbons were detected. The occurrence of highly adaptable microorganisms with an adequate metabolic potential in the petrochemical oily sludge deposit implies that its bioremediation is possible without introducing special microorganisms.

Metabolic Engineering. Integrating Methodologies of Molecular Breeding and Bioprocess Systems Engineering.

Metabolic engineering is an integrating methodology of analysis and synthesis for the improvement of flux distribution of metabolic pathways in complicated bioprocesses, which are highly multi-hierarchical systems to extend from macroscopic to microscopic levels. Recent progress in metabolic engineering methodologies to improve metabolic pathways in microorganisms was reviewed with many studies in this paper. Metabolic flux distribution was analyzed under different environmental conditions, using a metabolic reaction model. The physiological states of microorganisms were understood by interpreting metabolic flux analysis (MFA). This analysis was also used for development of process operation and control strategy. Cell capability to form a targeted product was analyzed with a metabolic reaction model and linear programming (LP). The use of a 13C-enriched carbon source and nuclear magnetic resonance (NMR) and gas chromatography-mass spectrometry (GCMS) analyses of intracellular and extracellular metabolites enabled determination of a metabolic flux distribution more accurately than the flux distribution determined only by the metabolic reaction model, which involves not only metabolite balances but also energy and redox balances. The comparison of metabolic flux distributions between before and after genetic modification of cells yielded information on the mechanism of regulation of metabolic flux in microorganisms. Finally, integration of bioinformatics and metabolic engineering is discussed, and cyclic modification of the complex bionetwork and process development were emphasized.

Device for sterile online measurement of the oxygen transfer rate in shaking flasks

The oxygen transfer rate (OTR) is the most suitable measurable parameter to quantify the physiological state of a culture of aerobic microorganisms since most metabolic activities depend on oxygen consumption. Online measurement of the oxygen transfer rate in stirred bioreactors is state of the art although technically difficult. However, the online determination of the oxygen transfer rate in shaking bioreactors under sterile conditions has not been possible until recently. A newly developed measuring device eliminates this deficit. Extremely useful information about cultivating conditions and the physiological state of microorganisms can be gained in early stages of research and bioprocess development from many reactors operated in parallel.

Regulation of the biomass and activity of soil microorganisms by microfauna

Microcosm experiments showed that the microbial biomass and the respiration activity in soil were regulated by nematodes. Depending on nematode number and plant residue composition, the trophic activity of nematodes can either stimulate or inhibit microbial growth and respiration as compared to soil containing no nematodes. The stimulating effect was observed when nitrogen-free (starch) or low-nitrogen (wheat straw, C:N = 87) organic substrates were applied. Inhibition occurred when a substrate rich in nitrogen (alfalfa meal, C:N = 28) was decomposed and the nematode population exceeded the naturally occurring level. A conceptual model was developed to describe trophic regulation by microfauna (nematodes) of the microbial productivity and respiration activity and decomposition of not readily decomposable organic matter in soil. The stimulating and inhibiting influence of microfauna on soil microorganisms was not a linear function of the rate of microbial consumption by nematodes. These effects are largely associated with the induced change in the physiological state of microorganisms rather than with the mobilization of biogenic elements from the decomposed microbial biomass.

Biocalorimetry and laser flow cytometry for characterization of the physiological state of microorganisms

The physiological state of microorganisms should be considered in biotechnology since this influences the rate and efficiency of cellular processes. Biocalorimetry and laser flow cytometry are suitable techniques for the description of the physiological state of microorganisms.

Characterization of the Physiological State of Microorganisms Using the Respiration Electrode

Abstract The respiration electrode - a new type of microbial sensor comprising small amounts of viable microorganisms on an oxygen electrode - was used for characterization of the physiological state of cells by measuring the change of respiration after substrate addition, (for example glucose by Bacillus subtilis as well as glucose and methanol by Candida boidinii). This respiration parameter - designated as acceleration of respiration - alters characteristically during a growth cycle, and is useful in following the physiological state of microorganisms.

Study of the physiological state of microorganisms in continuous cultures.

Study of the physiological state of microorganisms in continuous cultures.