Degradation Kinetics of Microbial Consortium Isolated from Diesel Oil Impacted Soil in Delta Park, University of Port Harcourt, Nigeria

Abstract

Heavy-duty generators constitute a form of hydrocarbon pollution but enrich microorganisms to having degradative ability of hydrocarbons hence can be used for remediation. In this study a laboratory treatability (biodegradation screening) study was employed to investigate the hydrocarbon degradation competence of bacteria and fungi. Culture-dependent microbiological and physicochemical analyses was conducted on the soil samples obtained from the polluted site. The total aerobic heterotrophic bacterial and fungi counts increased from 5.0-7.5 (Log10 cfu/mL) between day 0-14 then reduced to 6.5 Log10 cfu/mL. The hydrocarbon-utilizing bacteria increased from 4.5-5.2 (Log10 cfu/mL). Percentage degradation hydrocarbons, attributed to fungi bacteria and bacteria/fungi consortia, were 42.3%, 54% and 70% respectively while the control had 6.0%. The total petroleum hydrocarbon (TPH) removal rate (K) was modelled using the first order kinetics: y=-0.0398x+9.79; K=0.0398d-1. These results, correspond to a degradation efficiency of 70% and t1/2 of 17 days for the bacterial/fungal consortium. The K values for the other setups were 0.019 d-1, 0.0261 d-1 and 0.0022 d-1 with the corresponding degradation efficiencies of 42%, 54% and 6.01% and half-life of 37 days, 27 days and 315 days for fungi, bacteria and control respectively. This result indicates that the use of microbial consortia has high potentials in remediation of hydrocarbons and other pollutants of concern.

Bioremediation of heavy metals from artisanal crude oil refinery (Kpo-Fire) impacted soil using Bacillus flexus and Pseudomonas aeruginosa in Ngie Community, Degema Local Government Area, Rivers State, Nigeria

“…have been reported in some articles to produce organic materials that possess biosurfactant or emulsification properties and thereby increasing the solubility and bioavailability of components for microbial activities (Effiong et al, 2019;Sampson et al, 2016). This study agrees strongly with the report of Udume et al (2019) who reported the preponderance of Bacillus spp and Pseudomonas sp from their separate investigations, especially spore formers. This further concretizes the report of Orji et al (2018) that microbes and their diversity correlate with the diversity of organic substances produced as a result of adaptation to the environmental fluxes.…”

“…These parameters are crucial in the monitoring of the environmental quality of a media especially in the interaction of exchangeable cations, while the temperature factor indicates the solubility of nutrients and formation of metal-oxide complexes (Orhohoro et al, 2018). Furthermore, Chima and Vure (2014) suggested that the pH and temperature indices of the soil were also related to the geochemical indices such as the soil pore-sizes, air-quality and permeability (Effiong et al, 2019). The concentration of Boron in the soil sample was 3.6 mg/kg; Mercury was 1.05mg/kg with the DPR target value of 0.30mg/kg and intervention value of 10mg/kg.…”

“…This also agrees with the report of Chikere and Ekwuabu (2014) whose study alluded to the same range. Udume et al (2019) reported that diesel polluted soil obtained from the generator house in Delta Campus of the University of Port Harcourt could have a microbial count with the same range of 3.0-5.0 Log10CFU/g of the polluted soil.…”