[Degradation of the EDTA and EDTA complexes with metals by immobilized cells of Chelativorans oligotrophicus LPM-4 bacteria].

Enzymatic oxidative degradation of EDTA and EDTA complexes with metals has been investigated using immobilized cells of Chelativorans oligotrophicus LPM-4. A polarographic method, which makes it possible to register oxygen consumption by cells, has been used. For the first time, it has been indicated that the Cd-EDTA and Ni-EDTA complexes undergo degradation by the bacteria under study.

[Degradation of p-toluenesulfonate by immobilized Comamonas testosteroni BS1310 (pBS1010) cells].

Parameters of degradation of p-toluenesulfonate (TS) by free and agar-embedded Comamonas testosteroni BS1310 (pBS1010) cells were determined. The maximum rate of TS degradation was 25% lower in by immobilized than free cells, equaling 11 nmol x min(-1) x mg(-1) cells. Degradation of TS by both free and immobilized cells was associated with molecular oxygen consumption (molar ratio, 1 : 2). In a plug-flow reactor, the degradation rate was 10.4 nmol x min(-1) x mg(-1) cells. The results can be applied to designing reactors for TS degradation in sewage and developing biosensors.

[Biosensor of the reactor type based on Rhodococcus erythropolis HL TM-1 cells for determining 2,4-dinitrophenol]. / Biosensor reaktornogo gipa na osnove kletok Rhodococcus erythropolis HL PM-1 dlia opredeleniia 2,4-dinitrofenola.

A model of a reactor-type biosensor based on the Rhodococcus erythropolis HL PM-1 was developed for amperometric detection of 2,4-dinitrophenol (2,4-DNP). The effects of the matrix material (agar and calcium alginate gels, ceramic support, and cellulose powder) on the biosensor signal concentration dependence, detection time, and biosensor stability were studied. In case of bacterial cells immobilized on cellulose powder, the lower limit of 2,4-DNP detection was 20 microM and the time of single analysis, the biosensor recovery included, was 30-50 min. In the continuous detection mode, the biosensor response was maintained at a stable level without biosensor inactivation for ten days. The biosensor can be used as an element of a complex analytical system for detecting nitroaromatic compounds in samples.

[Degradation of 2,4-dinitrophenol by free and immobilized cells of Rhodococcus erythropolis HL PM-1]. / Degradatsiia 2,4-dinitrofenola svobodnymi i immobilizovannymi kletkami Rhodococcus erythropolis HL PM-1.

Degradation of 2,4-dinitrophenol (2,4-DNP) by the cells of Rhodococcus erythropolis HL PM-1 was studied. The enzymes involved in 2,4-DNP degradation were inducible, and their resynthesis took place during the process. Cell immobilization by embedding into agar gels decreased the degrader activity. Maximum rates of 2,4-DNP degradation by free and immobilized cells were 10.0 and 5.4 nmol/min per mg cells, respectively. The concentration dependence of 2,4-DNP degradation was typical of substrate inhibition kinetics. The immobilized cells were used in a model reactor designed for 2,4-DNP biodegradation. Its maximum capacity was 0.45 nmol/min per mg cells at a volumetric flow rate of 20 h-1. The reactor operated for 14 days without losing capacity; its half-lifetime equaled 16 days.

[Development of biosensors for phenol determination from bacteria found in petroleum fields of West Siberia]. / Bakterii iz pochv mestorozhdenii Zapadnoi Sibiri kak osnova biosensorov dlia opredeleniia fenola.

Nine Gram-negative bacterial strains, selected from 300 strains isolated from soils of the West Siberian petroliferous basin and growing on oil and oil products, consume phenol as a single carbon and energy source. The strains were used for the development of a sensor bioreceptor. The most active 32-I strain was shown to bear a plasmid responsible for phenol degradation. The plasmid-free derivative of this strain, 32-I-1, did not grow on phenol. The possibility of creating a model biosensor for phenol based on the plasmid-containing 32-I strain is considered. The detection limit for phenol was 5 microM. The optimum conditions for the sensor operation are: pH 7.4, 35 degrees C, and operation time 30 h.