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The content of heavy metals in the water bodies increases as a result of anthropogenic effects. Heavy metals exert toxical effect on hydrobionts. Involved into the trophic chain they can be the cause of grave human diseases. Microorganisms possess a capacity to accumulate heavy metals in their body, evoke the process of their enzymatic transformation into nontoxical compounds and adsorb them on the cell surface. When breeding bacterial strains for the biological treatment of sewage from the metal-working plants the authors recommend to choose the cultures from econiches containing heavy metal compounds and to establish their resistance to high concentrations of metals. This resistance correlates with high biological activity. The bacterial strains of Pseudomonas genus possessing a capacity to sulphate reduction have been selected. As a result of their activity the high-solvable toxical sulphates are restored to practically unsolvable precipitating forms. A new species Aeromonas dechromatica transforming high-toxical six-valence chromium into low-toxical three-valent ones is described. The grounds of biotechnologies of the use of the breeded cultures for treatment of industrial sewage are stated.

In the C. tropicalis K-41 cells fixed by glutaraldehyde and osmium most membranes consisted of two electron-transparent and one electron-dense layer. Morphologo-structural peculiarities of the cell fraction grown at 39 degrees testify to a certain disconnection of energetic and constructive metabolism, inhibition of synthetic processes. Cell division was more active at 29 degrees.

Brevibacterium flavum 22 and 22L producing lysine and glutamic acid should be reclassified as Corynebacterium glutamicum on the basis of their chemotaxonomic characteristics: the IV type of the cell wall, corynomycolic acids C32--C34, 57.8% of GC in DNA.

A large number of bacterial strains assimilating chemical ethanol has been isolated using an original technique. Active growth of strains belonging to the genera Pseudomonas and, particularly, Acinetobacter was registered on mineral media containing ethanol. A mathematical model was constructed select a strain of Acinetobacter calcoaceticus K-9 during its continuous cultivation on media containing ethanol. The model makes it possible to determine conditions for producing a present amount of the biomass, the percentage of its yield, and the produc;iveness as a function of the dilution rate, temperature, and the concentration of ethanol and phosphoric acid in the medium. The main characteristics of the growth process in the studied factor space were established. The optimum conditions were calculated for growth of the strain with respect to each of the criteria. Under various conditions of bacterial growth, changes in the morphology and ultra-fine structure of the cells correlated with their physiological activity. The volume of the cells increased with the rate of dilution of the medium: the process can be described by a saturation curve. The presence of mesosomal structures is typical of the cells growing at low flow rates.

The melting points of DNA were used to determine the nucleotide composition of DNA from the following microorganisms with a high growth rate: Mycobacterium phlei, M. smegmatis, M. fortuitum, Nocardia asteroides, the organism of the "rhodochrous"--N. opaca group, and organisms related to strain "Mycobacterium" rhodochrous ATCC 13808. M. fortuitum had a higher mol% G+C (67.5--69.5) than M. phlei (66.9--67.5) and M. smegnatis (64.4--68.1); the strains of M. smegmatis were characterized by the most heterogeneous nucleotide composition of DNA. The organisms of the "rhodochrous" complex (mol% G+C=69.5--72.2) were closer to N. asteroides (mol% G+C=72.5--73.5) than to the mycobacteria with a high growth rate.

Lactic bacteria predominate in the microflora of the digestive tract of chicken and turkey. They are represented mainly by Lactobacillus acidophilus, L. salivarius, L. fermentum and L. buchneri. Streptococcus faecium is always isolated. L. ruminis, L. vitulinus, L. delbrueckii, L. coryniformis and L. viridescens were found in this ecological niche for the first time. S. faecium and S. faecalis prevail in the digestive tract of geese and ducks, while lactobacilli are detected in a lesser amount and are represented mainly by L. plantarum. L. salivarius cells isolated from the digestive tract of poultry are highly polymorphous. Most of the lactic acid bacteria found in the digestive tract of poultry can grow at 45-50 degrees C whatever is the species they belong to.

Lactic acid bacteria were either absent or present in negligent quantities in the stomach of apparently healthy man. But in case of various pathological processes in the stomach and duodenum lactic acid bacteria accumulated (up to a million cells per 1 ml of gastric contents). Under these conditions coccal forms sharply prevailed over the bacillary ones. In patients with chronic gastritis and peptic ulcer of the stomach the most frequent were Streptococcus faecalis and its variants; in oncological patients--Str. faecium, strains affiliated to Leuconostoc mesenteroides, and sometimes Str. durans.

The ability to assimilate n-alkanes form hexane to decane was studied among 495 collection strains and 27 freshly isolated strains belonging to the genus Pseudomonas. All freshly isolated strains and over one third of collection cultures of Ps. aurantiaca grow on mineral media with n-alkanes of low molecular weight, but do not assimilate heavy paraffins. The strains of Ps. aeruginosa, Ps. fluorescens and Ps. putida, isolated from oilbearing soils, and individual collection cultures, belonging to the two latter species, can assimilate both n-alkanes of low molecular weight (C6--C10) and heavy paraffins. Contrary to Ps. aurantiaca, other species of the Pseudomonas genus lose the ability to assimilate n-alkanes of low molecular weight after cultivation on rich organic media. An increase in the concentration of the mixture of low molecular weight paraffins (to 20 per cent by volume) has no toxic effect on the Pseudomonas bacteria whose biomass has a high content of protein and all necessary amino acids. The strains of Ps. aurantiaca produce a highly active antibiotic preparation consisting of floroglucine derivatives on the defined medium with n-alkanes of low molecular weight. The ratio between components of the preparation obtained on the media with n-alkanes and on the optimal organic media is different.

The effect of biotin on the specific growth rate of Candida tropicalis was studied on media with various sources of carbon nutrition at temperatures of 29 and 39degreesC. The yeast was found to require 3--5 times less biotin on the medium with paraffin than on the medium with glucose and hexodecane, and 3--4 times more biotin on the same substrate with an increase in temperature. The growth rate increased by 36--40% on liquid paraffins containing 0.5 mcg/litre of biotin at 29degreesC and 1.5--2.0 mcg/litre of biotin at 39degreesC. The saturation constant of biotin increased from 0.033 to 0.063 mcg/litre on the medium with paraffin, and more by an order on the medium with glucose and hexadecane, at a rise of growth temperature from 29 to 39degreesC.

Synthesis of protein and amino acids by the thermotolerant yeast Candida tropicalis K-41 was studied at various temperatures of cultivation during growth on media with hydrocarbons in conditions of continuous cultivation. The content of protein in the cells decreased by 6% with an increase in growth temperature by 10 degrees C (from 29 to 39 degrees C) while excretion of free amino acids into the medium increased. The cultural broth of the cells grown at 39 degrees C contained up to 8 amino acids, with alanine, aspartic acid, serine and glycine prevailing. The content of amino acids which liberated into the medium decreased in the intracellular pool. However, the total amount of free amino acids in the system "cell--medium" remained constant at various temperatures of cultivation. Synthesis of free amino acids does not presumably limit total synthesis of protein by the yeast.