The degradation of Total Petroleum Hydrocarbons (TPH) in petroleum-contaminated clay soil remains a major environmental concern, particularly in regions with limited remediation options. This study investigates the enzymatic kinetics of TPH biodegradation using Michaelis-Menten modeling in the presence of Bryophyllum pinnatum leaf extracts as biostimulants. Fourteen bioreactors containing 2000g of contaminated clay soil were prepared with 100ml of crude oil and treated with varying doses (100ml, 200ml, and 300ml) of ethanol- and water-based Bryophyllum pinnatum extracts. Physicochemical and microbiological analyses were performed over a 42-day period. The kinetic parameters—maximum degradation rate (Vmax) and Michaelis-Menten constant (Km)—were derived using Lineweaver-Burk plots. Results showed that ethanol extracts were more effective than water extracts in enhancing microbial degradation of TPH. The highest Vmax (4000 ppm/day) and Km (1.068 ppm⁻¹) were recorded in T11, treated with 300ml ethanol. The regression coefficients (R² values) from linearized kinetic models ranged between 0.8432 and 0.9752, indicating strong correlations and model reliability. Bacterial counts were significantly higher in ethanol-treated samples compared to controls, suggesting enhanced microbial proliferation and degradation efficiency. The study concludes that biostimulant type and dosage influence the enzymatic behavior of hydrocarbon degradation and that Michaelis-Menten modeling is a reliable tool to quantify these dynamics. This approach supports the optimization of bioremediation strategies for petroleum-contaminated clay soils.

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1. Agarry, S.E., Ogunleye, O.O., & Audu, T.O.K. (2013). Biodegradation of crude oil in soil by indigenous microorganisms. Chemical and Process Engineering Research, 12, 34-45.
2. Agarry, S.E., & Ogunleye, O.O. (2015). Modeling bioremediation kinetics of crude oil-contaminated soil. International Journal of Environmental Bioremediation & Biodegradation, 3(1), 10-19.
3. Aghalibe, O., Ibekwe, C., & Okoli, C. (2017). Biodegradation kinetics of petroleum hydrocarbons in soil using compost and sawdust. Nigerian Journal of Technology, 36(3), 819–825.

4. Amagbo, O.E., & Ere, D. (2019). Bioremediation potential of cow dung in oil-polluted soil. African Journal of Environmental Science and Technology, 13(5), 176-185.
5. Asgari, F., Khosravi, R., & Ghanavati, H. (2017). Kinetic modeling of crude oil degradation using bacteria. Journal of Environmental Chemical Engineering, 5(3), 2535–2543.
6. Kumar, M., Dwivedi, R., & Singh, B. (2019). Role of microorganisms in petroleum degradation: A review. International Journal of Environmental Sciences, 10(1), 101–108.
7. Xue, Q., Zhu, H., & Yu, Y. (2018). Mechanisms of microbial hydrocarbon degradation. Applied Microbiology and Biotechnology, 102(3), 1239-1251.
8. Okoh, A.I. (2006). Biodegradation alternative in the cleanup of petroleum hydrocarbon pollutants. Biotechnology and Molecular Biology Reviews, 1(2), 38-50.
9. Vidali, M. (2001). Bioremediation: An overview. Pure and Applied Chemistry, 73(7), 1163-1172.
10. Atlas, R.M., & Bartha, R. (1998). Microbial Ecology: Fundamentals and Applications. Benjamin/Cummings Publishing.
11. Alexander, M. (1999). Biodegradation and Bioremediation (2nd ed.). Academic Press.

 The degradation of Total Petroleum Hydrocarbons (TPH) in petroleum-contaminated clay soil remains a major environmental concern, particularly in regions with limited remediation options. This study investigates the enzymatic kinetics of TPH biodegradation using Michaelis-Menten modeling in the presence of Bryophyllum pinnatum leaf extracts as biostimulants. Fourteen bioreactors containing 2000g of contaminated clay soil were prepared with 100ml of crude oil and treated with varying doses (100ml, 200ml, and 300ml) of ethanol- and water-based Bryophyllum pinnatum extracts. Physicochemical and microbiological analyses were performed over a 42-day period. The kinetic parameters—maximum degradation rate (Vmax) and Michaelis-Menten constant (Km)—were derived using Lineweaver-Burk plots. Results showed that ethanol extracts were more effective than water extracts in enhancing microbial degradation of TPH. The highest Vmax (4000 ppm/day) and Km (1.068 ppm⁻¹) were recorded in T11, treated with 300ml ethanol. The regression coefficients (R² values) from linearized kinetic models ranged between 0.8432 and 0.9752, indicating strong correlations and model reliability. Bacterial counts were significantly higher in ethanol-treated samples compared to controls, suggesting enhanced microbial proliferation and degradation efficiency. The study concludes that biostimulant type and dosage influence the enzymatic behavior of hydrocarbon degradation and that Michaelis-Menten modeling is a reliable tool to quantify these dynamics. This approach supports the optimization of bioremediation strategies for petroleum-contaminated clay soils.

🔒 This is a subscription article

Full text is available to subscribers and institutional members. Please choose an option below to access it.

1. Agarry, S.E., Ogunleye, O.O., & Audu, T.O.K. (2013). Biodegradation of crude oil in soil by indigenous microorganisms. Chemical and Process Engineering Research, 12, 34-45.
2. Agarry, S.E., & Ogunleye, O.O. (2015). Modeling bioremediation kinetics of crude oil-contaminated soil. International Journal of Environmental Bioremediation & Biodegradation, 3(1), 10-19.
3. Aghalibe, O., Ibekwe, C., & Okoli, C. (2017). Biodegradation kinetics of petroleum hydrocarbons in soil using compost and sawdust. Nigerian Journal of Technology, 36(3), 819–825.

4. Amagbo, O.E., & Ere, D. (2019). Bioremediation potential of cow dung in oil-polluted soil. African Journal of Environmental Science and Technology, 13(5), 176-185.
5. Asgari, F., Khosravi, R., & Ghanavati, H. (2017). Kinetic modeling of crude oil degradation using bacteria. Journal of Environmental Chemical Engineering, 5(3), 2535–2543.
6. Kumar, M., Dwivedi, R., & Singh, B. (2019). Role of microorganisms in petroleum degradation: A review. International Journal of Environmental Sciences, 10(1), 101–108.
7. Xue, Q., Zhu, H., & Yu, Y. (2018). Mechanisms of microbial hydrocarbon degradation. Applied Microbiology and Biotechnology, 102(3), 1239-1251.
8. Okoh, A.I. (2006). Biodegradation alternative in the cleanup of petroleum hydrocarbon pollutants. Biotechnology and Molecular Biology Reviews, 1(2), 38-50.
9. Vidali, M. (2001). Bioremediation: An overview. Pure and Applied Chemistry, 73(7), 1163-1172.
10. Atlas, R.M., & Bartha, R. (1998). Microbial Ecology: Fundamentals and Applications. Benjamin/Cummings Publishing.
11. Alexander, M. (1999). Biodegradation and Bioremediation (2nd ed.). Academic Press.