Development Of Other Microorganisms Research Articles

Study of the dynamics of the development of lactic acid microorganisms in the two-stage process of fermenting cabbage varieties "Parus"

Relevance. Leuconostoc mesenteroides, Lactobacillus plantarum and Leuconostoc fallaxare the three main lactic acid bacteria developing in the production of sauerkraut. The process of production of fermented foods, as well as their characteristics are determined by the fermenting activity of microorganisms used. Many food products (matured cheeses, sauerkraut, etc.) are canned products: for them, the term is significantly increased compared to the shelf life of the raw material from which these products are made. Their characteristic feature is not only high stability during storage, but also a pronounced flavor bouquet, due to the direct or indirect action of fermenting microorganisms.Material and methods. Microbiological methods of preserving fruits and vegetables are based on the formation of natural preservatives – lactic acid and alcohol, which accumulate as a result of fermentation of sugars by lactic acid bacteria or yeast. The intensity of lactic acid fermentation and the amount of accumulated lactic acid depend on several conditions: the presence of lactic acid bacteria, the content of sugars and other chemicals in the raw material, the addition of spice-aromatic plants, anaerobic conditions, temperature. Due to the accumulation of lactic acid, the development of other microorganisms, and then the lactic acid bacteria themselves, is suspended. The dynamics of development of lactic acid microorganisms and their consortia on the model media, pretreated by the culture of Leuconostoc mesenteroides species, at the main stage of step fermentation of white cabbage of the "Parus"variety are investigated.Results. Dynamics of development of monocultures of L. brevis, L. casei and L. plantarum and their paired consortia at the main technological stage at two stages of fermentation are investigated. It is established that a preliminary fermentation of a model medium with a culture of Leuconostoc mesenteroides generates adverse conditions for the development of L. brevis and L. casei in the monoculture (pseudotensorial) and in consortium with each other, but favorable conditions for the development of L. plantarum in pseudotensorial and in pairwise combinations with L. brevis and L. casei.

Prospects for the Use of New Technologies to Combat Multidrug-Resistant Bacteria.

The increasing use of antibiotics is being driven by factors such as the aging of the population, increased occurrence of infections, and greater prevalence of chronic diseases that require antimicrobial treatment. The excessive and unnecessary use of antibiotics in humans has led to the emergence of bacteria resistant to the antibiotics currently available, as well as to the selective development of other microorganisms, hence contributing to the widespread dissemination of resistance genes at the environmental level. Due to this, attempts are being made to develop new techniques to combat resistant bacteria, among them the use of strictly lytic bacteriophage particles, CRISPR–Cas, and nanotechnology. The use of these technologies, alone or in combination, is promising for solving a problem that humanity faces today and that could lead to human extinction: the domination of pathogenic bacteria resistant to artificial drugs. This prospective paper discusses the potential of bacteriophage particles, CRISPR–Cas, and nanotechnology for use in combating human (bacterial) infections.

A new cell primo-culture method for freshwater benthic diatom communities

A new cell primo-culture method was developed for the benthic diatom community isolated from biofilm sampled in rivers. The approach comprised three steps: (1) scraping biofilm from river pebbles, (2) diatom isolation from biofilm, and (3) diatom community culture. With a view to designing a method able to stimulate the growth of diatoms, to limit the development of other microorganisms, and to maintain in culture a community similar to the original natural one, different factors were tested in step 3: cell culture medium (Chu No 10 vs Freshwater “WC” medium modified), cell culture vessel, and time of culture. The results showed that using Chu No 10 medium in an Erlenmeyer flask for cell culture was the optimal method, producing enough biomass for ecotoxicological tests as well as minimising development of other microorganisms. After 96 h of culture, communities differed from the original communities sampled in the two rivers studied. Species tolerant of eutrophic or saprobic conditions were favoured during culture. This method of diatom community culture affords the opportunity to assess, in vitro, the effects of different chemicals or effluents (water samples and industrial effluents) on diatom communities, as well as on diatom cells, from a wide range of perspectives.

Antibiotics for non-human uses.

Abstract

RESEARCHES CONCERNING MICROBIOLOGICAL EVOLUTION OF LACTIC ACID BACTERIA TO YOGHURT STORAGE DURING SHELF-LIFE

Lactic acid bacteria evolution ( Lactobacilus delbrueckii ssp bulgaricus and Streptococcus termophilus ) was followed in tree stages of storage: in first day of storage after processing; in the middle of storage during s helf-life; in the last day of storage during shelf-life. For yoghurt, the manufacture depends on a symbiotic relationship between two bacteria, Streptococcus thermophilus and Lactobacillus bulgaricus, where each species of bacterium stimulates the growth of the other. The a im of this study was to research in which way lactic acid bacteria evolved (concentrati on of viable cells) to storage during shelf-life. The method for determination of lactic acid bacter ia was conforming Romanian standard SR ISO 13437/1999 and was used enrich and isolation microbial mediums . Also, from the same samples was determined and total yeast and molds. 5 samples of yoghurt were taken in study and determination was made at s torage, during shelf-life. A decrease of concentration of lactic acid bacter ia was observed to storage, especially in the last decade of shelf-life to all samples taken in study. Concentration of lactic acid bacteria witch should be from 10 7 ufc/gram until the end of shelf-life is registered only in the first day of product storage ..The end of shelf-life the concentration was very low, by 10 4 ufc/gram (witch is consider inadequate). Also, in 15% from total samples taken in study, wer e observed that in the last decade of storage, lactic acid bacteria are inhibit ed by yeast and molds. The concentration continues to decrease until the end of shelf-life. This indicate a low stability of starter culture in fermented dairy, the viable germs being inhibited by the development of other microorganisms, primarily Enterobacteriaceae and then yeasts and molds.