[Use of claydite-immobilized oil-oxidizing microbial cells for purification of water from oil].

Oil-oxidizing bacteria were isolated from oil-polluted soil and water samples and identified as Acinetobacter calcoaceticus K-4, Nocardia vaceinii K-8, Rhodococcus erythropolis EK-1, and Mycobacterium sp. K-2. It was found that immobilization of the bacteria on an expanded clay aggregate accelerated their growth and consumption of hydrocarbon substrates. It was also found that water polluted with 100 mg/l oil could be purified with Rhodococcus erythropolis EK-1 and Nocardia vaceinii K-8 cells immobilized in this way. The dependence of the degree of water purification on its flow rate, aeration, and availability of nitrogen and phosphorus sources was determined. The efficiency of water purification from oil by immobilized Rhodococcus erythropolis EK-1 cells at high flow rates (of up to 0.68 l/h), low aeration (of 0.1 l/l per min) and an intermittent supply of 0.01% diammonium phosphate reached 99.5-99.8%.

The structure of bacterial cell cycle and age structure of bacterial populations.

Study of synchronous and asynchronous cultures of Bacillus megaterium, Bacillus thuringiensis and Bacillus licheniformis has shown that the duration of chromosomal DNA replication (period C) is proportional to the generation time, and time between two cycles of the DNA replication (known as period I). The duration of period C is nearly constant and makes up from 0.5 to 1.0 hour at the variations of the generation time from 1.5 to 2.75 hours. The duration of period B (the time between the termination of the cell division and initiation of DNA replication), and period D (the time between the termination of DNA replication and initiation of cell division) were experimentally revealed as stochastic parameters. The theoretical model of the bacterial cell cycle and the age structure of bacterial population was suggested. The main points of this theory are that periods C and I may be stochastically disposed in the division cycle of individual cells and a sum of duration of C- and I-periods is equal to generation time. The data calculated from the theoretical model were confirmed by the experimental data of flow cytofluorometric analysis of the age structure of synchronous and asynchronous cultures of the bacilli.

[The use of the neustonic forms of bacilli for purifying and decontaminating reservoirs]. / Ispol'zovanie neistonnykh form batsill dlia ochistki i obezzarazhivaniia vodoemov.

It is shown possible to select the bacterial strains which are neuston ones, i.e., concentrating on the water-atmosphere interface. The preparation based on the neuston form of Bacillus megaterium is more efficient for purification of water polluted with oil hydrocarbons than the preparation based on the planktonic form of the same culture. Preparation based on the neuston form of the aerobic spore-forming bacteria is effective for biological decontamination of sewage treated using conventional methods. Application of neuston bacterial forms permits intensifying the microbiological processes in the thin (15-40 microM) surface layer of water bodies.

[Age specificity of the interaction of Bacillus cells with a liquid-gas interface]. / Vozrastnaia spetsifichnost' vzaimodeistviia kletok batsill s poverkhnost'iu razdela zhidkost'-gaz.

The age specificity of the bacilli cells with liquid--gas interface was studied using flow cytofluorometry. This interactions is dependent on the position of the cell in the division cycle and not on the position of the cell in the DNA replication cycle.

[The autoselection of neustonic forms of bacteria]. / Avtoselektsiia neistonnykh form bakterii.

Self-breeding of neuston forms of Methylobacterium sp., Pseudomonas putida BC-2, Alcaligenes paradoxus BC-1, Bacillus thuringiensis var. israilensis bacteria as well as of a mixed culture of methylotrophs is shown possible. In spite of ability of hydrophobicity of the cell surface the suggested method of self-breeding may be used to perfect properties of larvicidal biopreparations, and bacterial preparations which intensify self-purification of water bodies.

[The flotation characteristics of Bacillus cells and spores]. / Osobennosti flotatsii kletok i spor batsill.

Variations in hydrophobicity of the surface of bacillary cells and their capacity to flotation in the process of batch cultivation have been studied. It is shown that hydrophobicity of the cell surface increases in the course of batch cultivation of Bacillus thuringiensis, B. licheniformis and B. megaterium. Hydrophobicity of spores of the mentioned cultures is considerably higher than that of the vegetative cells. The increase of hydrophobicity of bacillary cells positively correlated with their capacity to flotation. That is why the use of flotation for the age fractionation of bacillary cells is possible: spores are concentrated in the foam while vegetative cells remain in the culture liquid.