[Microbial sensors: achievements, problems, prospects]. / Mikrobnye sensory: dostizheniia, problemy, perspektivy.

The review summarizes the literature data on the design of laboratory and commercial types of biosensors based on living cells of microorganisms. The following aspects are discussed: microbiological, biochemical and physical fundamentals of microbial sensors; operation modes and fields of application of cell-based biosensors; immobilization technique for biological recognition systems; benefits and problems in this field of biotechnology.

[Use of conductometric microsensors for studying kinetic parameters of enzymes]. / Ispol'zovanie konduktometricheskikh mikrosensorov dlia izucheniia kineticheskikh parametrov fermentov.

An alternative method based on thin-film conductometric microsensor is suggested for studying enzyme kinetics. It is established that the immobilized enzyme as well as soluble one is described by the classic lows of enzyme kinetics. Major parameters (Km and Vmax) are identical to those measured by the widely used methods and their amounts are 1.33 mM and 9.04 microS/min for soluble urease and 3.73 mM and 13.8 microS/min for immobilized urease; 5.26 mM and 13.9 microS/min for immobilized glucose oxidase; 13.6 mM and 122.0 microS/min for immobilized acetyl cholinesterase; 10.8 mM and 129.9 microS/min for immobilized butyryl cholinesterase. The possibility of conductometric analyzer application for detection of toxin concentration, in particular pesticides, is shown. Advantages and disadvantages of the system suggested are discussed.

[Cellular microbiosensors for methanol and ethanol determination on the basis of pH-sensitive field transistors]. / Kletochnye mikrobiosensory na osnove pH-chuvstvitel'nykh polevykh tranzistorov dlia opredeleniia metanola i étanola.

Cellular sensors for methanol and ethanol determination were developed using immobilized mutant cells of methylotrophic yeasts Hansenula polymorpha and Pichia pinus (able to extrude protons in the presence of alcohol) and pH-sensitive field effect transistors (pH-SFETs). The intact cells of yeasts were immobilized in Ca-alginate gel to obtain a biomembrane. The minimal detectable response was obtained to approximately 0.5 mM of methanol and ethanol, a linear dependence of biosensor's response on the logarithmic alcohol concentration was observed in the range from 5 to 100 mM for both types of alcohol. The prospects for application of biosensors to determine alcohols in the analytical practice are discussed.

[Quantitative photometric analysis of ethanol using purified alcohol oxidase and mutant cells of methylotrophic yeast]. / Kil'kisnyi fotometrychnyi analiz etanolu z vykorystanniam ochyshchenoï alkohol'oksydazy ta mutantnykh klityn metylotrofnykh drizhdzhiv.

The photometric method is suggested for ethanol analysis by means of purified alcohol oxidase isolated from a wild strain of methylotrophic yeast Hansenula polymorpha. Three different chromogenic systems for peroxidative oxidation together with alcohol oxidase reaction have been used. For the first time the intact cells of the catalase-negative mutant as a source of alcohol oxidase are employed in the photometric alcohol assay. The prospects for application of the latter method for practical purposes are discussed.