Screening and isolation of pesticides-degrading bacteria from activated sludge

Abstract

Screening and isolation of pesticides-degrading bacteria from activated sludge study was carried out to identify the degrading bacteria of pesticides. Pesticides degrading bacterial were isolated from activated sludge of Indah Water Konsortium Sdn Bhd. It was found that six isolates had been purified and then grown on nutrient agar with temperature 37oC. Bacteria growth shown the log phase of bacteria is the first 24 hours and the exponential phase was the second day which was after 24 hours to 48 hours. The stationary phase is third day which was 48 hours to 72 hours and the death phase started after 72 hours which is after four days. Then, strains were identified through identification such as gram staining and API 20 E test. After laboratory test, six of the strains were identified as gram negative. Three of the strains were cocci-shaped bacterial while the other three strains were rod-shaped bacteria. The expected genus included Staphylcoccus, Escherichia, Thiobacillus, and Arthrobacter and so on. The API 20 E test has resulted Acinetobacter baumanni/calcoaceticus for four strains, one strain was Pseudomonas oryzihabitans and another one strain was Chryseobacterium nebingosepticum. The strains then been tested on pesticides, Niclosamide Etahnolamine and Fentin Acetate. Out of all strains, only Strain 1 and Strain 3 have potential as pesticides-degrading bacteria.