Isolation and Characterization of Carbofuran - Degrading Bacteria from Malaysian Soil
Bacteria isolates isolated from soil samples were screened for the ability to degrade Carbofuran. One hundred and fifty isolates isolated from various locations in Selangor, Perak and Johor were screened for the ability to degrade Carbofuran. Five isolates gave positive results with varying degre...
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| Format: | Thesis |
| Language: | English |
| Published: |
2005
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/5944/1/FBSB_2005_23%20IR.pdf |
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| Summary: | Bacteria isolates isolated from soil samples were screened for the ability to degrade
Carbofuran. One hundred and fifty isolates isolated from various locations in
Selangor, Perak and Johor were screened for the ability to degrade Carbofuran. Five
isolates gave positive results with varying degrees of degradation. Based on these
results, bacterial Isolate 147 Pseudomonas sp. isolated from Bukit Ekspo Universiti
Putra Malaysia (UPM) Selangor campus was selected for further studies due to its
ability to completely degrade Carbofuran in the minimum amount of time. This
bacterium grew on Carbofuran as a sole source of nitrogen in a minimal salts medium.
It showed the ability to degrade Carbofuran present in the minimal salts medium
containing 100 mgll Carbofuran as nitrogen source. MTT 13-(4,5-dimethyl-2-
thiazoly1)-2,5 diphenyl tetrazolium bromide] assay was used to screen bacteria
capable of degrading pesticides indicated by the change in colour of the tetrazolium
salt from yellow to blue. This bacterium reduced the tetrazolium salt which act as on
electron acceptor for the formation of blue formazan. The growth optimization of
Isolate 147 was investigated under various conditions. Optimum growth was obtained
at 30°C and pH 8 an additional carbon source such as glucose was needed to provide
sufficient energy for the degradation to occur. It also grew abundantly in high
concentration of 100mgIl Carbofuran. The degradation of Carbofuran by Isolate 147
was analysed using High Performance Liquid Chromatography (HPLC). This
bacterium was able to degrade Carbofuran up to 93.03 % after six days incubation in
the minimal salt medium. Enzyme produced by Isolate 147 during Carbofuran
degradation was partially purified by 3.6 fold with ion exchange chromatography with
an overall yield of 72.6%. It was shown to have a K, value of 448.5 pM, optimum
activity at 30°C and pH 8. |
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