Enhanced Carbofuran Degradation Using Immobilized and Free Cells of Enterobacter sp. Isolated from Soil.

Mohammed Umar Mustapha,Wan Lutfi Wan Johari,Mohd Yunus Abd Shukor,Normala Halimoon

doi:10.3390/molecules25122771

Mohammed Umar Mustapha, Wan Lutfi Wan Johari + Show 2 more

Open Access

https://doi.org/10.3390/molecules25122771

Copy DOI

Abstract

Extensive use of carbofuran insecticide harms the environment and human health. Carbofuran is an endocrine disruptor and has the highest acute toxicity to humans than all groups of carbamate pesticides used. Carbofuran is highly mobile in soil and soluble in water with a lengthy half-life (50 days). Therefore, it has the potential to contaminate groundwater and nearby water bodies after rainfall events. A bacterial strain BRC05 was isolated from agricultural soil characterized and presumptively identified as Enterobacter sp. The strain was immobilized using gellan gum as an entrapment material. The effect of different heavy metals and the ability of the immobilized cells to degrade carbofuran were compared with their free cell counterparts. The results showed a significant increase in the degradation of carbofuran by immobilized cells compared with freely suspended cells. Carbofuran was completely degraded within 9 h by immobilized cells at 50 mg/L, while it took 12 h for free cells to degrade carbofuran at the same concentration. Besides, the immobilized cells completely degraded carbofuran within 38 h at 100 mg/L. On the other hand, free cells degraded the compound in 68 h. The viability of the freely suspended cell and degradation efficiency was inhibited at a concentration greater than 100 mg/L. Whereas, the immobilized cells almost completely degraded carbofuran at 100 mg/L. At 250 mg/L concentration, the rate of degradation decreased significantly in free cells. The immobilized cells could also be reused for about nine cycles without losing their degradation activity. Hence, the gellan gum-immobilized cells of Enterobacter sp. could be potentially used in the bioremediation of carbofuran in contaminated soil.

Highlights

Pesticide use in agriculture can cause undesirable effects on humans and the natural environment, and different types of toxic organic compounds are being released accidentally or intentionally into the environment [1]
Based on the biochemistry performed, the isolate was citrate-positive, catalase-negative, oxidase, and non-spore forming bacteria. 16S rRNA gene sequence analysis was done to compare with related sequences available in the NCBI GenBank, and the strain BRC05 showed high similarity with the genus Enterobacter sp
Local soil bacteria were isolated from agricultural farms in Malaysia and identified as Enterobacter species by using 16S rRNA sequencing

Summary

Introduction

Pesticide use in agriculture can cause undesirable effects on humans and the natural environment, and different types of toxic organic compounds are being released accidentally or intentionally into the environment [1]. Pesticides are introduced frequently in large volumes via different means [2]. Though carbofuran is chemically unstable as a result of easy hydrolysis in the environment, carbofuran residues are mostly discovered in groundwater because of its extensive use and high mobility in soils [6]. Their removal from the environment is essential [7,8]

Methods

Results

Conclusion