RU106898U1 - DEVICE FOR EXPRESS DETERMINATION OF BIOCHEMICAL OXYGEN CONSUMPTION - Google Patents

Abstract

 A device for the rapid determination of biochemical oxygen consumption, containing a measuring cell, a magnetic stirrer and a biosensor system including an oxygen electrode on which immobilized microorganisms are placed, characterized in that Debaryomyces hansenii BKM Y-2482 yeast is used as immobilized microorganisms.

Description

The technical solution relates to the field of ecology, namely, to biosensor analytical devices. The device can be used for rapid determination of biochemical oxygen consumption (MIC) in water samples of various origins.

To assess the degree of water pollution by biodegradable organic compounds, a parameter is currently used, defined as an index of biochemical oxygen consumption. The existing method for determining BOD is based on tests, the minimum duration of which is 5 days [PNDF 14. 1: 2: 3: 4. 123-97. Quantitative chemical analysis of water. The methodology for measuring biochemical oxygen demand after n-days of incubation (BICfill) in surface fresh, underground (ground), drinking, wastewater and treated wastewater. - M.: 1997.25 p.]. Currently, all enterprises, sanitary services and wastewater treatment plants of the Russian Federation use the standard method for everyday wastewater analysis. The lack of efficiency significantly reduces the value of the traditional method. For this reason, environmentally hazardous situations arise in which the flow of accidentally contaminated waters to the wastewater treatment plants or vice versa, their under-treatment during regeneration, goes unnoticed.

For operational analysis, BOD assessment methods based on the use of biosensor analyzers can be used. In B PC biosensors, microorganisms capable of oxidizing a wide range of organic compounds were used as recognition elements.

The closest in its features adopted for the prototype is a device for the rapid determination of the MIC of wastewater from food industry enterprises described in [Arlyapov V.A., Ponomareva O.N., Alferov V.A., Rogova T.V., Blokhin I.V., Chepkova I.F., Reshetilov A.N. Microbial biosensors for express determination of BOD of wastewater from food industry enterprises. // Water: Chemistry and Ecology. 2008. No. 3, from 23-30.]

The measuring system consisted of an amperometric oxygen electrode with immobilized microorganisms. As microorganisms, we used the yeast Arxula adeninivorans VGI (78) -6, or the bacteria Gluconobacter oxydans subsp. industrus BKM B-1280. The immobilization of microorganisms was carried out by adsorption on a glass fiber Whatman GF / A filter. The measurements were carried out with constant stirring in an open cuvette with a working volume of 5 ml. The biosensor based on the Arxula ademnovorans yeast had the best characteristics and allowed to determine BOD ₅ in the range of 1.4-11.6 mg / dm ³ (without diluting the sample), the biosensor's stable operation time was 28 days.

The objective of the proposed technical solution is to improve the technological capabilities of the device, due to the fact that the device allows the determination of biochemical oxygen consumption after n-days of incubation in surface fresh, underground (ground), drinking, waste and treated wastewater in the range of 0.5-180 mg / dm ³ (without sample dilution) for 10 minutes

The essence of the technical solution lies in the fact that the device for the rapid determination of BOD containing a measuring cuvette, a magnetic stirrer and a biosensor system including an oxygen electrode on which immobilized microorganisms are placed, and Debaryomyces hansenii BKM Y-2482 yeast used as immobilized microorganisms.

Figure 1 shows a device for the rapid determination of biochemical oxygen consumption, which is an oxygen electrode with immobilized microorganisms, coupled to a measuring cell and a magnetic stirrer.

Figure 2 shows a diagram of substrate specificity (sensitivity) of the bioreceptor used.

Table 1 shows the characteristics of the proposed utility model and prototype.

The proposed device consists of the following elements: a biosensor, consisting of a transducer - an oxygen electrode 1, on which a bioreceptor 2 is placed, representing go and immobilized on a carrier cells of the strain Debaryomyces hansenii VKM Y-2482. An oxygen electrode 1 with a bioreceptor 2 is placed in a measuring cell 3 with a volume of 4 ml. Mixing the solution in the measuring cell 3 is carried out using a magnetic stirrer 4 with an anchor 5.

To register the signal of the biosensor system, a device is used that determines the dependence of current on time - the Electrochemical testing system IPC2000, connected to an oxygen electrode and a computer.

To form the receptor element of the microbial biosensor, the yeast strain Debaryomyces hansenii VKM Y-2482 belonging to the All-Russian Collection of Microorganisms is used. To obtain biomass, microorganisms were grown on a rich mineral medium (liquid glucose-peptone nutrient medium). The composition of the liquid medium: glucose - 10 g / dm ³ , peptone - 5 g / dm ³ , yeast extract - 0.5 g / dm ³ , distilled water - 200 cm ³ . The cell growth medium was autoclaved at a pressure of 1 atmosphere for 45 minutes. Cells were grown aerobically for 18-20 hours in rocking flasks with a volume of 750 cm ³ at a temperature of 29 ° C.

The principle of operation of the device for the rapid determination of biochemical oxygen consumption is as follows:

An oxygen electrode 1 with a bioreceptor 2 placed on it containing immobilized cells of the strain Debaryomyces hansenii VKM Y-2482 is immersed in a measuring cuvette 3 of 4 ml volume with 30 mM phosphate buffer (pH 6.8) and the current reflecting the oxygen content in the medium is recorded (background). Then make a sample containing biodegradable organic substances (100 μl). The measurements are carried out with continuous stirring using a magnetic stirrer 4 with anchor 5 at room temperature.

After registering the biosensor signal (current versus time), the cell is washed with a buffer solution. The value of the maximum oxygen consumption rate (sensor response, dI / dt, nA / s) is calculated and the value of BOD ₅ is determined from the previously constructed calibration curve. The calibration dependence is based on a solution of glucose-glutamate mixture (GHS) prepared according to RFP 14. 14: 2: 3: 4. 123-97. In accordance with the specified regulatory document, it was accepted that BOD ₅ , equal to 205 mg / dm ³ , corresponds to a solution containing a total of 300 mg / dm ³ glucose and glutamic acid.

Microorganisms Debaryomyces hansenii BKM Y-2482 are able to oxidize a wide range of organic substances, which makes it possible to obtain a high degree of correlation between the biosensor readings of the system and the standard method.

Table 1 presents the characteristics of the proposed device for the rapid determination of biochemical oxygen consumption and prototype.

The linear range of the dependence of the response of the biosensor from BOD ₅ lies in the range of 0.5-180 mg / dm ³ (without dilution of the sample). The duration of a single measurement does not exceed 10 minutes. Long-term stability of the sensor for more than 60 days (the decrease in the activity of microorganisms during this time was 25%).

Thus, the proposed device for the rapid determination of biochemical oxygen consumption provides the ability to expressly determine the BOD index for no more than 10 minutes in the range of 0.5-180 mg / dm ³ (without diluting the sample) without the use of sophisticated expensive equipment.

Claims (1)

A device for the rapid determination of biochemical oxygen consumption, containing a measuring cell, a magnetic stirrer and a biosensor system including an oxygen electrode on which immobilized microorganisms are placed, characterized in that Debaryomyces hansenii BKM Y-2482 yeast is used as immobilized microorganisms.