Isolation and Immobilization of Biosurfactant-Producing Bacteria Capable of Degrading Carbofuran Pesticide

Abstract

Pesticide residue has been detected not only on agricultural lands but also in bodies of water such as rivers, lakes, and the sea. This study was aimed at exploring the potency of local bacterial isolates to degrade carbofuran, an active pesticide compound. Two biosurfactant-producing bacteria were isolated from hydrocarbon-compound-contaminated seas (NF9) and agricultural land with a long-term history of pesticide application (AB2). Bacteria were selected according to their ability to grow on a mineral medium, Bushnell Haas Agar, with the addition of 41.86 ppm of carbofuran pesticide as the sole carbon source. Their growth was characterized morphologically, biochemically, and molecularly based on their 16S rRNA genes. All isolates were Gram+ and indicated as Bacillus thuringiensis KD168 for isolate NF9 and Bacillus paranthracis C9 for isolate AB2. Both of the isolates were immobilized in sodium alginate and polyurethane matrixes. Both B. thuringiensis NF9 and B. paranthracis AB2 were able to degrade carbofuran, as indicated by the presence of carbofuran residue that ranged from 1.03 to 1.89 ppm; however, the residue was undetected after 15 days of incubation. We also confirmed that bacterial cells were immobilized and retained in polyurethane as well as in the sodium alginate matrix. The immobilization of the bacterial cells showed the abilities of the cells to degrade pesticides and their potential to be developed as bioremediation agents in polluted areas.