[Biological denoxation of chemical pathogens in aqueous medium].

There are considered possibilities and perspectives of denoxation (decontamination) of chemical pathogens by means of biological methods for the environment sanitation and protection from contamination. There are presented numerous examples of successful practical application of the modern biotechnologies in industrial sewage denoxation from xenobiotics.

[Strains of Pseudomonas fluorescens 3 and Arthrobacter sp. 2--degradation of polycyclic aromatic hydrocarbons]. / Shtamy Pseudomonas fluorescens 3 ta Arthrobacter sp. 2--destruktory politsyklichnykh aromatychnykh vuglevodniv.

Pseudomonas fluorescences 3 and Arthrobacter sp. 2 strains were isolated from the association of microorganisms--destructors of oil hydrocarbons and were selected for their ability to grow on media with phenanthrene as the only source of carbon and energy. The P. fluorescens 3 strain is able to grow on naphthalene, fluorene, phenanthrene, and anthracene. Arthrobacter sp. 2 strain did not grow on naphthalene, but was able to destruct phenanthrene and fluorene. The destruction activity of these strains both in pure and mixed culture towards the latter compounds has been studied. The both strains destructed phenanthrene added into the medium in the amount of 0.2 g/l, and phenanthrene destruction by Pseudomonas fluorescences 3 achieved 98.5% in 6 days and that by Arthrobacter sp. 93.5% in 23 days. Bacterial growth has been evaluated while measuring protein concentration in samples. Bacteria were inoculated in quantities equivalent to 0.0015-0.0020 mg protein/l. The cell protein concentration achieved 35-40 mg/l for Pseudomonas fluorescences 3, and 85-92 mg/l for Arthrobacter sp. by the end of incubation.

[Genetic determination of degradation of ampholytic surfactants]. / Geneticheskaia determinatsiia razrusheniia amfolitnykh poverkhnostno-aktivnykh veshchestv.

Plasmid DNA was detected in Pseudomonas putida 141 and P. stutzeri AT strains which caused destruction of the ampholytic surfactants alkylamino-bis-propionate (AABP) and amidobetaine, respectively. As was demonstrated using genetic analytic procedures, the plasmids controlled AABP and amidobetaine destruction. No plasmid DNA was found in P. desmolytica C37 which caused cyclimide destruction or in Pseudomonas sp. 1 and Citrobacter freundii TO strains responsible for AABP destruction. Apparently, destruction of these xenobiotics was controlled by chromosomal genes.

[Reduction of chromium (VI) by reference bacterial strains]. / Vosstanovlenie shestivalentnogo khroma kollektsionnymi shtammami bakterii.

Collection bacterial strains were found to be capable of chromium (VI) reduction although they had not been in contact with chromium compounds before. Strains capable of nitrate respiration could use bichromate ions as a terminal electron acceptor in the absence of competing acceptors. Cr(VI) was reduced to Cr(III) when bichromate was added to the cultural broth whose redox potential reached -140 mV.

[Anaerobic glove box]. / Anaérobnyi perchatochnyi boks.

Anaerobic conditions can rapidly be created in a box designed for working with obligate anaerobic organisms by driving out the air with an inflatable ball. The box is fitted with a device for sterilising a microbiological loop.

[Microorganisms destroying a number of nonionogenic surface-active substances]. / Mikroorganizmy--destruktory riada neionogennykh poverkhnostno-aktivnykh veshchestv.

Microorganisms destroying nonionogenic surfactants (NS) were selected. The isolated cultures were assigned to the genera Pseudomonas and Bacillus. Biodestruction of 19 NS was studied in Erlenmeyer flasks with shaking and in the course of continuous cultivation. The rate of destruction was shown to depend on the chemical structure of a substance: block-copolymers of ethylene and propylene oxides were more resistant to the action of microorganisms. The results indicate that sewage waters containing NS (at an initial concentration of 50 to 500 mg/l) can be purified on local installations using microbial cultures or their complexes.

[Transformation of p-nitrochlorobenzene by Escherichia coli]. / Transformatsiia p-nitrokhlorbenzola Escherichia coli.

Microorganisms that have not been adapted to p-nitrochlorobenzene (p-NCB) are capable of transforming this compound. Washed cell of Escherichia coli, the resting culture and the homogenate of disintegrated cells transform p-NCB into p-chloroaniline (p-CA). The growing culture of E. coli (Eh = -210 mV) reduces the nitro group of p-NCB. If E. coli cells are separated from the cultural broth under strictly anaerobic conditions, the redox potential rises abruptly (Eh = -110 mV); the filtrate does not transform p-NCB into p-Ca. The rate at which E. coli reduces the nitro group of p-NCB depends on the redox potential of the medium. It is likely that any microorganism is capable of reducing p-NCB at a low value of the redox potential.

[Electroretention of microorganisms]. / Elektrouderzhivanie microorganizmov

Water is liberated from microbial cells in the course of flow of microbial suspensions through dielectrics and conductors of the second kind in electric field. Microorganisms are retained by electrophoresis and dielectrophoresis, polarization of the cells and particles, electrostatic, dipole-dipole interaction between them. When the current is switched off, the cells are liberated and washed out with small volumes of water, and the regenerated material may be used several times for separating microbial cells from fluids. Effectiveness of retainment of microorganisms increases with an increase in voltage and a decrease in the flow rate.

[Characteristics of spore-forming bacteria of the genus Bacillus that break down caprolactam]. / Kharakteristika sporoobrazuiushchikh bakterii roda Bacillus, razrushaiushchikh kaprolaktam

Five strains of sporeforming bacteria were isolated from sewage of capron industry and their morphological, cultural, as well as physiological and biochemical properties were investigated. Four strains were identified as Bacillus subtilis and one as Bacillus pumilus. The cultures were able to grow in mineral medium with caprolactam as a source of carbon and nitrogen. The influence of growth conditions on the rate of caprolactam decomposition in synthetic medium was studied.