Organizing co mmittee

 
 

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Poster presentation 
205 
ISOLATION OF MICROORGANISMS AND THEIR USE IN THE 
PROCESS OF DEGRADATION OF PESTICIDES 
D.I. Kosimov, L.I. Zaynitdinova, A.M. Mavjudova, R.B. Ergashev
Institute of Microbiology of the Academy of Sciences of the Republic of Uzbekistan, 7B 
A. Kadyri str., Tashkent, Uzbekistan 
Pesticides are extremely toxic chemicals, and their use is increasing year by year. 
This causes an increase in the amount of pesticide residues in soil, water and other 
objects, and as a result, environmental pollution. As a result of intensive use of 
pesticides in violation of the norms and rules of their use, soils are exposed to 
particularly strong destructive effects. The natural processes of soil self-cleaning cannot 
cope with such a volume of pollution, because the local microflora is inhibited as a 
result of high soil toxicity. Therefore, it is important to isolate destructive 
microorganisms and use them in the treatment of contaminated soils.
Isolation of microorganisms was done using gray soil treated with pesticides 
(cypermethrin, chlorpyrifos, etc.). Soil samples were taken from a depth of 0-15 cm. 
First, the soil was dried in laboratory conditions, then it was cleaned from various plant 
residues, small stones and other inclusions and passed through a stainless steel sieve 
with a diameter of 2 mm. One kg of soil was additionally contaminated with a mixture 
of chlorpyrifos + cypermethrin pesticides, and in order to enrich this soil with 
microorganisms, it was treated with the liquid part of the sludge of the biogas plant, and 
then it was kept in a thermostat at 30 ° C for one month to adapt the microorganisms to 
the pesticide environment. A total of 17 microorganism isolates were isolated. As a 
result of their growth and high biomass production in pesticide environments, isolate 
No. 3 showed the best performance and was selected for further research. In laboratory 
conditions, the morpho-cultural characteristics of this isolate were studied, and MALDI-
TOF MS analysis was carried out, and the nucleotide sequence was determined based 
on 16 S rRNA. The obtained results showed that this bacterium belongs to the species 
Ochrobactrum intermedium
. This strain was registered in the NCBI database with the 
corresponding number (GenBank: OL587509.1.).
Further studies were conducted to determine the degradation of chlorpyrifos (100 
mg/kg) and cypermethrin (40 mg/kg) pesticides based on Ochrobactrum intermedium 
PDB-3 strain. Researches were conducted in sterile soils for a period of one month. Soil 
samples were taken for chromatographic analyses, initially, after 15 and 30 days. 
Bacteria-free soil contaminated with pesticides was used as a control. 
The obtained results showed that the chlorpyrifos pesticide with an initial 
concentration of 100 mg/kg on the basis of 
Ochrobactrum intermedium
PDB-3 strain 
was reduced to 20.7 mg/kg within one month, and the degradation rate was 79.3%. No 
cypermethrin residues were detected in soil samples taken at the end of the study, and it 
was found that cypermethrin with an initial concentration of 40 mg/kg was completely 
degraded within 30 days.