Crude oil contamination remains a persistent environmental burden in petroleum-producing regions, and low-cost, locally sourced plant-leaf biostimulants offer a promising route to accelerate hydrocarbon-degrading microbial activity in impacted soils. This study evaluated the bacterial and fungal population dynamics accompanying biostimulated bioremediation of crude-oil-contaminated sandy, loamy, and clay soils amended with room-dried or sun-dried Dacryodes edulis, Canarium schweinfurthii, and Persea americana leaves at 50 g or 100 g doses, monitored over 42 days across 36 treatment bioreactors and three unamended controls. First- and second-order kinetic models were fitted to total petroleum hydrocarbon (TPH) depletion data, and total heterotrophic bacterial (THB) and fungal (THF) counts were enumerated in parallel. First-order kinetics best described the majority of treatments (R2 generally > 0.98), with rate constants of 0.035–0.067 day⁻¹ and half-lives of 10.3–19.8 days. Soil type was the dominant determinant of TPH removal (ANOVA, F = 612.5, p < 0.001), with mean removal following sandy (93.2%) > loamy (88.6%) > clay (75.5%) soil, while biostimulant species, drying method, and dose showed no statistically significant effect. All biostimulated treatments substantially outperformed unamended controls (2.4- to 2.7-fold higher removal). THB counts peaked around Day 28 before declining, and this bacterial fold-increase correlated significantly with TPH removal (r = 0.49, p = 0.0026), whereas fungal population growth did not (r = 0.01, p = 0.96). These findings indicate that soil texture, more than biostimulant identity, governs degradation outcome, and that bacterial rather than fungal proliferation drives hydrocarbon removal under these leaf-based biostimulation regimes.
| Published in | Science Discovery Environment (Volume 1, Issue 3) |
| DOI | 10.11648/j.sdenv.20260103.12 |
| Page(s) | 151-165 |
| Creative Commons |
This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium or format, provided the original work is properly cited. |
| Copyright |
Copyright © The Author(s), 2026. Published by Science Publishing Group |
Bioremediation, Biostimulation, Crude Oil Degradation, Soil Texture, Hydrocarbon-utilizing Bacteria
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APA Style
Nyong, T. E., Peter, U. C. (2026). Kinetics and Microbial Population Dynamics of Leaf-Biostimulated Crude Oil Bioremediation in Contrasting Soils. Science Discovery Environment, 1(3), 151-165. https://doi.org/10.11648/j.sdenv.20260103.12
ACS Style
Nyong, T. E.; Peter, U. C. Kinetics and Microbial Population Dynamics of Leaf-Biostimulated Crude Oil Bioremediation in Contrasting Soils. Sci. Discov. Environ. 2026, 1(3), 151-165. doi: 10.11648/j.sdenv.20260103.12
AMA Style
Nyong TE, Peter UC. Kinetics and Microbial Population Dynamics of Leaf-Biostimulated Crude Oil Bioremediation in Contrasting Soils. Sci Discov Environ. 2026;1(3):151-165. doi: 10.11648/j.sdenv.20260103.12
@article{10.11648/j.sdenv.20260103.12,
author = {Tuboalabo Eno Nyong and Ukpaka Chukwuemeka Peter},
title = {Kinetics and Microbial Population Dynamics of
Leaf-Biostimulated Crude Oil Bioremediation in Contrasting Soils},
journal = {Science Discovery Environment},
volume = {1},
number = {3},
pages = {151-165},
doi = {10.11648/j.sdenv.20260103.12},
url = {https://doi.org/10.11648/j.sdenv.20260103.12},
eprint = {https://article.sciencepublishinggroup.com/pdf/10.11648.j.sdenv.20260103.12},
abstract = {Crude oil contamination remains a persistent environmental burden in petroleum-producing regions, and low-cost, locally sourced plant-leaf biostimulants offer a promising route to accelerate hydrocarbon-degrading microbial activity in impacted soils. This study evaluated the bacterial and fungal population dynamics accompanying biostimulated bioremediation of crude-oil-contaminated sandy, loamy, and clay soils amended with room-dried or sun-dried Dacryodes edulis, Canarium schweinfurthii, and Persea americana leaves at 50 g or 100 g doses, monitored over 42 days across 36 treatment bioreactors and three unamended controls. First- and second-order kinetic models were fitted to total petroleum hydrocarbon (TPH) depletion data, and total heterotrophic bacterial (THB) and fungal (THF) counts were enumerated in parallel. First-order kinetics best described the majority of treatments (R2 generally > 0.98), with rate constants of 0.035–0.067 day⁻¹ and half-lives of 10.3–19.8 days. Soil type was the dominant determinant of TPH removal (ANOVA, F = 612.5, p loamy (88.6%) > clay (75.5%) soil, while biostimulant species, drying method, and dose showed no statistically significant effect. All biostimulated treatments substantially outperformed unamended controls (2.4- to 2.7-fold higher removal). THB counts peaked around Day 28 before declining, and this bacterial fold-increase correlated significantly with TPH removal (r = 0.49, p = 0.0026), whereas fungal population growth did not (r = 0.01, p = 0.96). These findings indicate that soil texture, more than biostimulant identity, governs degradation outcome, and that bacterial rather than fungal proliferation drives hydrocarbon removal under these leaf-based biostimulation regimes.},
year = {2026}
}
TY - JOUR T1 - Kinetics and Microbial Population Dynamics of Leaf-Biostimulated Crude Oil Bioremediation in Contrasting Soils AU - Tuboalabo Eno Nyong AU - Ukpaka Chukwuemeka Peter Y1 - 2026/09/29 PY - 2026 N1 - https://doi.org/10.11648/j.sdenv.20260103.12 DO - 10.11648/j.sdenv.20260103.12 T2 - Science Discovery Environment JF - Science Discovery Environment JO - Science Discovery Environment SP - 151 EP - 165 PB - Science Publishing Group SN - 3071-5431 UR - https://doi.org/10.11648/j.sdenv.20260103.12 AB - Crude oil contamination remains a persistent environmental burden in petroleum-producing regions, and low-cost, locally sourced plant-leaf biostimulants offer a promising route to accelerate hydrocarbon-degrading microbial activity in impacted soils. This study evaluated the bacterial and fungal population dynamics accompanying biostimulated bioremediation of crude-oil-contaminated sandy, loamy, and clay soils amended with room-dried or sun-dried Dacryodes edulis, Canarium schweinfurthii, and Persea americana leaves at 50 g or 100 g doses, monitored over 42 days across 36 treatment bioreactors and three unamended controls. First- and second-order kinetic models were fitted to total petroleum hydrocarbon (TPH) depletion data, and total heterotrophic bacterial (THB) and fungal (THF) counts were enumerated in parallel. First-order kinetics best described the majority of treatments (R2 generally > 0.98), with rate constants of 0.035–0.067 day⁻¹ and half-lives of 10.3–19.8 days. Soil type was the dominant determinant of TPH removal (ANOVA, F = 612.5, p loamy (88.6%) > clay (75.5%) soil, while biostimulant species, drying method, and dose showed no statistically significant effect. All biostimulated treatments substantially outperformed unamended controls (2.4- to 2.7-fold higher removal). THB counts peaked around Day 28 before declining, and this bacterial fold-increase correlated significantly with TPH removal (r = 0.49, p = 0.0026), whereas fungal population growth did not (r = 0.01, p = 0.96). These findings indicate that soil texture, more than biostimulant identity, governs degradation outcome, and that bacterial rather than fungal proliferation drives hydrocarbon removal under these leaf-based biostimulation regimes. VL - 1 IS - 3 ER -