Document Details

Document Type : Thesis 
Document Title :
Biodegradation of the organ phosphorus inseciticide Diazinon by bacteria isolated from rhizosphere of date palm grow in western region
التحلل الحيوي للمبيد الفسفور عضوي دايازنون بواسطه البكتيريا المعزولة من رايزوسفير نخيل التمر من المنطقة الغربية
 
Subject : Faculty of Sciences 
Document Language : Arabic 
Abstract : Due to widespread use pesticides for crop protection, they are considered as contaminants in the, environmental matrices such soil which are exposed to large quantities. Three isolates from soil samples were isolated at 45ᵒC using enrichment culture technique and minimal salt medium (MSM) where Diazinon served as a sole carbon source (60 mg/l). Total three bacterial strains were screened for Diazinon degradation. The most active one was isolate BMNF7 (33% degradation). Lower degradation percentages were recorded for the two other isolates BMRF3 and BMTF8 (21-30%). The isolates were identified by morphological and biochemical studies as Pseudomonas earuginosa, Bacillus safensis and Leucobacter sp. Moreover, identification was confirmed using 16SrRNA. These isolate was able to degrade Diazinon in mineral salt agar and broth media containing Diazinon as a sole carbon source. The degradation time of Diazinon were 11-17 days for the three tested bacteria while it was 40 day in control medium. There is a synergistic relationship between Pseudomonas earuginosa and Bacillus safensis. and antagonistic interactions between Bacillus safensis and Leucobacter sp. Thus, the effect of different growth factors on growth and Diazinon degradation were determined for B. safensis and Pseudomonas aeruginosa. Addition of low concentrations of yeast extract and glucose as an additional carbon and nitrogen sources accelerated the Diazinon degradation. The maximum degradation was obtained at pH 6-7 and 45ᵒC after 10-13 days of incubation and using 4x106 CFU/ml as inoculum size. It was noticed that the best growth temperature was 37ᵒC while the maximum degradation was at 45ᵒC, meaning that high temperature increased degradation process. It is found that immobilization of bacterial cells on either luff or calcium alginate as supports increased degradation. Diazinon degradation was the maximum in yellow palm followed by red and dry palm. Degradation of Diazinon was maximum in non sterile soil or in soil inoculated with a mixture of the isolates BMRF3+ BMNF7 compared to inoculated sterile soil. In conclusion the bacterial strains isolated from the agricultural soil, especially showed the ability to degrade Diazinon and optimization of growth conditions enhanced the percentage of degradation. 
Supervisor : Prof. Dr. Magda Mohammed Ali 
Thesis Type : Doctorate Thesis 
Publishing Year : 1438 AH
2017 AD 
Co-Supervisor : Prof. Dr. Fahad Abdullarman Alfassi 
Added Date : Thursday, June 15, 2017 

Researchers

Researcher Name (Arabic)Researcher Name (English)Researcher TypeDr GradeEmail
بثينة علي العيدروسAlaidaroos, Bothaina AliResearcherDoctorate 

Files

File NameTypeDescription
 40910.pdf pdf 

Back To Researches Page