Optimization of Fruit Garbage Enzymes Requirements for Biocatalytic Remediation of Used Motor Oil-Contaminated Soil

Abstract

Objectives : In this research work, we investigated the biocatalytic potency of orange and watermelon garbage enzymes in the remediation of used motor oil-contaminated soils. The optimization of the biocatalytic remediation process was evaluated through D-optimal of response surface methodology (RSM) design of design expert.Methods : The optimization of the biocatalytic process was evaluated with D-optimal model of response surface methodology (RSM) design, where input variables in the system were garbage enzymes solutions of orange and watermelon peels (biocatalysts) and two different pollution levels. The two levels of pollution factor considered were 5 and 10 % (w/w) oil pollution levels and used as independent variables; while the response of the system was in oil and grease (O&G) removal as dependent variables that were monitored under 6-week remediation process.Results and Discussion : The result indicated that the model was highly significant and good predictors of the response fate of oil and grease (O&G) removal by the orange and watermelon garbage enzymes, as indicated by their coefficients of determination: R2 = 0.90627 and R2 = 0.88365 at p < 0.05, respectively. Therefore, it was observed from the numerical optimization carried out that 54.2 and 53.8 % O&G removal was achieved with orange garbage enzymes at 5 and 10 % pollution level respectively after six weeks. On the other hand, 54.7 and 55.2 % O&G removal was accomplished with the same pollution level respectively under the influence of watermelon garbage enzymes after six weeks of the remediation process.Conclusion : In response to what was achieved in this research work, the enzymes produced from the orange and watermelon garbage removed oil in terms of O&G from used motor oil-contaminated soils biocatalytically and hence could be applied in the remediation of oil contaminated soils.