Comparative study of microbial tolerance and degradation potentials to herbicides in crude oil-polluted soil
1 Department of Microbiology Technology, School of Science Laboratory Technology (SSLT), University of Port Harcourt, Port Harcourt, Rivers State Nigeria.
2 Department of Microbiology, Federal University of Technology, Owerri, Imo State PMB 1526, Nigeria.
Research Article
International Journal of Science and Technology Research Archive, 2026, 10(02), 010-021.
Article DOI: 10.53771/ijstra.2026.10.2.0017
Publication history:
Received on 09 March 2026; revised on 19 April 2026; accepted on 22 April 2026
Abstract:
This study isolated bacteria and fungi from crude oil-polluted soil and tested their tolerance and degradation potentials in the presence of glyphosate, paraquat and chlorpyrifos. Bacterial isolates and their percentage occurrence were Pseudomonas putida (29%), Bacillus cereus (18%), Bacillus subtilis (13%), Chromobacterium violaceum (11%), Clostridium sp. (8%), Serratia marcescens (8%), and Corynebacterium sp. (8%), while fungal isolates and their percentage occurrence were Fusarium sp. (13%), Aspergillus niger (34%), Rhizopus sp. (22%), Aspergillus terreus (13%), and Penicillium sp. (19%). The total heterotrophic bacteria and total fungal count from oil-polluted soil ranged between 1.15 - 9.75±0.22 × 104 cfu/g and between 0.5 - 4.4±0.35 × 103 sfu/g, respectively. Chromobacterium violaceum and A. niger were the most tolerant isolates. Both had a growth count of 4.7 and 2.9, respectively, in the presence of 1000 μg/l of glyphosate and a tolerance index of 1.35 and 0.83, followed by Bacillus subtilis and Penicillium sp. The degradation potential of Chromobacterium violaceum and A. niger was ascertained at an optical density of 540nm; Chromobacterium violaceum ranged between 0.1-0.5 (glyphosate), 0.2-1.0 (paraquat) and 0.2-1.0 (chlorpyrifos) while that of A. niger ranged between 1.0-3.1 × 102 sfu/mL (glyphosate), 1.8-2.2 × 102 sfu/mL (chlorpyrifos) and no growth was observed in paraquat. Bioremediation of glyphosate, paraquat and chlorpyrifos is a feasible technique using appropriate biodegraders. Bacteria and fungi show specificities in the degradation of herbicides and also at varying volumes of herbicides. Therefore, a consortium of microorganisms can be considered while seeking eco-friendly bioremediation solutions.
Keywords:
Agrochemical; Biodegradation; Microorganism; Mitigation; Pollution
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